msm: camera: correct the boundary check

cci transactions are optimized by comparing i2c addresses
in consecutive commands using pointer to command.
Correct the boundary check to ensure that pointers to command do
not go out of bounds.

Change-Id: I8846b13d78cb16c090ba6a4c59bd46d920748e2f
Signed-off-by: Xu Han <hanxu@codeaurora.org>