msm: camera: Add fix to avoid array index out of bound in cpp

  The parameter for number of buffers passed from user space
may be very large. While allocating memory, this could result
in integer overflow. As a result lesser memory will be allocated
then expected. This inturn may result in array index out of bound
error when the pointer is used to access memory.

  The fix is to limit the maximum requested buffers per stream. If
request is greater than the maximum value, error is returned back
to user space.

CRs-Fixed: 489273
Change-Id: I3d316f439610609cd36615eea3e68d0e8a0be0d7
Signed-off-by: Nishant Pandit <npandit@codeaurora.org>
(cherry picked from commit b7126cdd15b764bad8fe9fafe3dbd6ee3e8d44ec)