msm: camera: Restructure data handling to be more robust

Use dynamic array allocation instead of static array to
prevent stack overflow.
User-supplied number of bytes may result in integer overflow.
To fix this we check that the num_byte isn't above 8K size.

CRs-Fixed: 1060554
Change-Id: I9b05b846e5cc3a62b1a0a67be529f09abc764796
Signed-off-by: VijayaKumar T M <vtmuni@codeaurora.org>