msm_fb: call the backlight control before FB_BLANK_POWERDOWN

You might see the white line while lcd off. You should turn lcd backlight
off before lcd off to avoid that issue. So call the notifier for backlight
before handling of FB_BLANK_POWERDOWN in msm_fb.

Change-Id: I3bd08025a949ec02a1fba7cef98a13d8977c135b
msm: display: add sync point support in overlay commit

Wait for fence signaled before commit, signal previous
fence after commit done. Same as pan display

Signed-off-by: Ken Zhang <kenz@codeaurora.org>
Signed-off-by: Naseer Ahmed <naseer@codeaurora.org>

Conflicts:

	drivers/video/msm/mdp4_overlay.c
	drivers/video/msm/msm_fb.c

Conflicts:
	drivers/video/msm/msm_fb.c