msm: vidc: Amend calculation of buffer sizes in VENUS_BUFFER_SIZE

Add 8KB worth of padding for extradata. This is required to accommodate
some of the larger extradata types that didn't fit into the residual
space between the actual buffer size and its aligned size.

CRs-Fixed: 647378
Change-Id: I550f806079dfbdece229f68ffdfc5c0e20b3c9e1
Signed-off-by: Deva Ramasubramanian <dramasub@codeaurora.org>
msm: vidc: Expose extradata size to userspace

Previously, the extradata size was included within VENUS_BUFFER_SIZE
and callers (primarily in userspace) wouldn't know how much extra
padding was added to the buffer size. Exposing it allows userspace to
query directly instead of doing guesswork.

Change-Id: I7f9701a4adfe364d757028514bdd4fa84402a995
Signed-off-by: Deva Ramasubramanian <dramasub@codeaurora.org>
HACK: Workaround for broken camera driver

 * VENUS_BUFFER_SIZE is inlined all over userspace, including in the
   camera driver. The camera driver is ancient, and referenced the
   old calculation which does not include the 8K of padding for
   extradata.
 * Return zero here, so the padding is not included across userspace.
   This will fix the camera, but break several new video features.

 * This issue is a STOPSHIP and must be resolved before final release.

Change-Id: I9e02bd606ececafa13edcf476a261ef7ad39a710