Let's plug in your data for a TDEE (total daily energy expenditure) estimate. I don't know your age so I put in 30 as a rough estimate (close enough to a younger or middle age). I've selected a sedentary lifestyle, because in my opinion a raw TDEE estimate without formulas guessing your calories burned by activity is more useful as a baseline. You come out at an estimate of 2222 kcal per day. What a nice number! Note that this is an estimate. To get more accurate data you'd need to track your full calorie intake every day for a few weeks (at least two). Then weigh yourself every day (preferably right after waking up and going to the toilet and before drinking or eating). Then check the average weight every week and see if it changes to any significant degree. If it hardly changes over the course of a few weeks when eating about 2222 kcal every day, that's your average TDEE. If it drops, you're eating a bit below, if it rises, you're eating a bit too much. This is a good starting point to begin working on.
You'll need to create a caloric deficit through diet, exercise or a combination of the two.
My goal is to have visible abs by December 2016.
That's a fairly good start. Your goal is not unrealistic. With that time frame you could focus on a small caloric deficit to lose weight very gradually, which will be easier to do than an overly aggressive approach. But keep in mind that building muscle will be hard or impossible in a caloric deficit (it is feasible for beginners), so maybe the time frame is even a bit too long. At 185 cm, given your weight of 84 kg, I can't imagine your body fat percentage is really that high. 3 months might in fact be sufficient. Get your body fat low enough to bring out visible abs, then eat at maintenance to keep your physique, or slightly above your TDEE (which by then will have changed, so re-estimate or repeat the above experiment) in combination with weightlifting if you want to gain muscle. If you want to avoid new fat deposits, your gains in muscle and strength will necessarily have to be slow. So see if you're okay with that. If a pleasing look is your goal rather than raw strength or gaining a lot of lean body mass (and fat in the process), that's fine.
My workout plan is: 5 day per week
Cardio or weightlifting?
For weightlifting, there's a ton of programs out there. Which ones are suitable depends on your goal and whether you're a novice or intermediate. Unless you are accustomed to this volume, there's no need to work out 5 days per week. 3 or 4 days could get the job done just fine and would allow for better recovery. If you are going to work out 5 times a week AND you are not adapted to such volume, start the workouts light. Try to get each muscle group in twice a week.
For cardio, the same goes. Don't go overboard on volume unless you've built up the tolerance to it, and even then it's still a good idea to respect recovery. Cumulative fatigue can get the better of you. 5 moderate workouts per week could work well though, if it's more manageable than 4 or 3 more intense ones for you.
My diet plan is: 70% protean and 30carbs and have cheat day at 8th day
I'm not sure what you mean here. You want to get 70% of your calories from protein and 30% from carbs? This will not work for two reasons. The first is that you'd need to eat about 389 grams of protein at 2222 kcal per day. That is fairly insane. Not to mention completely unnecessary. 1.8 grams of protein per kilogram of (target) body weight is sufficient. Anything more than that is, according to all dependable sources I've seen on the subject, a waste. The second reason it wouldn't work is because you'd die. You need fat to survive. Literally. Of the three macronutrients, two are essential: protein and fat. You can do without carbohydrates, but the glycogen depletion would make working out pretty harsh. I'd say you should aim for about 25% protein MAX, then fill the rest of your daily allowed calories with fat and carbs. The ratio of those two will depend on your training. If for example you're already lifting a decent amount and would like to maintain strength as much as possible, some more carbs would help on the workouts. You could also cycle a bit: some more fat on some days, some more carbs on others (especially around training).
The cheat day isn't a bad idea, provided you don't go overboard and undo a lot of hard work over the week. On the "cheat" day (although you should call it a "break" day or "replenish" day) eat at your TDEE or slightly over it. Say, 250 kcal extra. It's a lot more maintainable, both physically and mentally, than a non-stop deficit for months. It could be useful to eat slightly less protein on that day and take advantage of a higher carb load, replenishing some glycogen for your workouts.