display: backlight: Relocate display_backlight_set/get/change_brightness() to reduce...

display: backlight: Relocate display_backlight_set/get/change_brightness() to reduce plugin duplication

Remove and redefine functions in the backlight_ops.
- set_brightness, get_brightness, transit_brt, get_brightness_raw
Wearable profile can have two status of get_brightness lbm_get_brightness/(default)get_brightness
That's why get_brightness_raw was put in backlight_ops to always call (default)get_brightness.
get_brightness_raw can be replaced by display_backlight_get_brightness.

These functions are added to below diplay-backlight.
int display_backlight_set_brightness(int brightness)
int display_backlight_get_brightness(int *brightness)
void display_backlight_change_brightness(int start, int end, int step)
-> With these functions, it is possible to get and set brightness through HAL.
int display_backlight_get_brightness_by_plugin_profile(int *brightness)
-> This function is temporary, it is for handling wearable profile dependency.
    To keep original code intent, this is necessary for functions that are dependent on wearable profile.

Change-Id: I0c9cb7675c39094576dd7e42d66d46a29da4144b
Signed-off-by: Yunhee Seo <yuni.seo@samsung.com>