Use division by integer for kinetic mouse key

Replace multiplication of fractional decimal numbers with
division by integer to avoid floating point operations.
This change will result with smaller compiled firmware size.

quantum/mousekey.c

@@ -175,7 +175,7 @@ static uint8_t wheel_unit(void) {
 /*
  * Kinetic movement  acceleration algorithm
  *
- *  current speed = I + A * T/50 + A * 0.5 * T^2 | maximum B
+ *  current speed = I + A * T/50 + A * (T/50)^2 * 1/2 | maximum B
  *
  * T: time since the mouse movement started
  * E: mouse events per second (set through MOUSEKEY_INTERVAL, UHK sends 250, the
@@ -196,7 +196,7 @@ static uint8_t move_unit(void) {
         speed = mousekey_accel & (1 << 2) ? mk_accelerated_speed : mk_decelerated_speed;
     } else if (mousekey_repeat && mouse_timer) {
         const uint16_t time_elapsed = timer_elapsed(mouse_timer) / 50;
-        speed                       = mk_initial_speed + MOUSEKEY_MOVE_DELTA * time_elapsed + MOUSEKEY_MOVE_DELTA * 0.5 * time_elapsed * time_elapsed;
+        speed                       = mk_initial_speed + MOUSEKEY_MOVE_DELTA * time_elapsed + (MOUSEKEY_MOVE_DELTA * time_elapsed * time_elapsed) / 2;
 
         speed = speed > mk_base_speed ? mk_base_speed : speed;
     }
@@ -216,7 +216,7 @@ static uint8_t wheel_unit(void) {
     } else if (mousekey_wheel_repeat && mouse_timer) {
         if (mk_wheel_interval != MOUSEKEY_WHEEL_BASE_MOVEMENTS) {
             const uint16_t time_elapsed = timer_elapsed(mouse_timer) / 50;
-            speed                       = MOUSEKEY_WHEEL_INITIAL_MOVEMENTS + 1 * time_elapsed + 1 * 0.5 * time_elapsed * time_elapsed;
+            speed                       = MOUSEKEY_WHEEL_INITIAL_MOVEMENTS + 1 * time_elapsed + (1 * time_elapsed * time_elapsed) / 2;
         }
         speed = speed > MOUSEKEY_WHEEL_BASE_MOVEMENTS ? MOUSEKEY_WHEEL_BASE_MOVEMENTS : speed;
     }