msm: camera: enhance global media controller lookup table

The existing global lookup table cannot handle the use case that
two camera devices uses the same image mode. Actually,
for the SoC camera its pixel image mode are only used for post
processing. Protection is added to enable this use case.

Change-Id: I2b560bdc32417a22f0198c948e9734381c2e8f70
Signed-off-by: Mingcheng Zhu <mingchen@codeaurora.org>
Signed-off-by: Kiran Kumar H N <hurlisal@codeaurora.org>