* fix(anim): relayout lv_anim_t to save 4 bytes
and fix the minor comment issue
* fix(anim): unify the type of time and animation to int32_t or uint32_t
since lv_anim_t use these types internally
* fix(anim): Don't need initialize last_task_run
since lv_anim_start will do this if the list is empty
and remove -1 to improve the accuracy
* fix(anim): remove the return value from anim_ready_handler
since no caller really use the return value
* fix(math): _lv_map check x >= max_in first
_lv_map return max_out when min_in equals max_in,
since the animation module require this behaviour
* fix(anim): normalize the time elapse by lv_map
* fix(anim): avoid iterate the list twice in anim_task
faf45419ca