display: Remove unused codes related to AMBIENT in display plugins
At first, ambient module is initialized by vconfkey "db/starter/always_on_display".
However, that vconfkey is not exist in profiles except the wearable profile, so
ambient module initialization fails in other profiles.
Furthermore, that vconfkey sets the device flag "AMBIENT_MODE" and "LCD_PHASED_TRANSIT_MODE".
Thus, AMBIENT_MODE/LCD_PHASED_TRANSIT_MODE flags cannot be used in iot-headed/mobile/tv profile.
All the unused codes related to AMBIENT_MODE/LCD_PHASED_TRANSIT_MODE flags will be removed
from iot-headed/mobile/tv plugins.
Change-Id: I6998151e9f1d6d1fc8c8035616a3dd621826e2d9
Signed-off-by: Yunhee Seo <yuni.seo@samsung.com>