target: msm8996: update early camera's flip mechanism

Early RVC can be controlled by GPIO, so before RVC's exit,
it's possible LK and kernel will update display hardware
at the same time after system is up. So to avoid sync
problem, early camera's flip can update the pipe only
after ping pong buffer are updated to hardware, it does
not need to update all display hardware registers.

CRs-Fixed: 2224864
Depends-on: 2273977
Change-Id: Ie9c6535faf25ae5a203258c465a525faa52f681c
Signed-off-by: Guchun Chen <guchunc@codeaurora.org>