msm: camera: Add lower and upper bounds check in msm_cpp.c ioctl()

Add a check for upper and lower bounds in msm_cpp_subdev_ioctl() for
command code VIDIOC_MSM_CPP_DEQUEUE_STREAM_BUFF_INFO.

CRs-fixed: 518731
Change-Id: I72996e13b7370a3b49f645297c52a118775b2b12
Signed-off-by: Seemanta Dutta <seemanta@codeaurora.org>