msm: camera: Fix various small issues in sensor driver

Add size check for zero the userspace arguments
before passing to kzalloc. Upper bound will be
max to uint16_t as these changes between different
sensors.

CRs-fixed: 507874
Change-Id: I13fb5740ab83c5719244d012a27d50abb26083d0
Signed-off-by: Hariram Purushothaman <hpurus@codeaurora.org>