msm: camera: isp: Handle more than one isp init packet

The new design requires ISP to handle multiple INIT packet when it comes.
The change adds the logic to merge the multiple INIT packet into one
single packet.

Change-Id: I90e35da09239b73517f8d34e1e01032333edbb03
Signed-off-by: Ravikishore Pampana <rpampana@codeaurora.org>
Signed-off-by: Jing Zhou <jzhou70@codeaurora.org>