msm-camera: Addressing possible overflow conditions

Changes to address possible integer overflow and incorrect
array indexing conditions.

CRs-Fixed: 897259
Change-Id: Ib134320cd6f7b34d7a10572ec347ec12127049a9
Signed-off-by: Trilokesh Rangam <tranga@codeaurora.org>
Signed-off-by: Yang Guang <guyang@codeaurora.org>
Signed-off-by: VijayaKumar T M <vtmuni@codeaurora.org>