msm: vidc: Make buffer validity checks stronger

Check for the exact number of planes that we advertised to the client
rather than the worst-case checks.

Signed-off-by: Deva Ramasubramanian <dramasub@codeaurora.org>

Bug: 26425736

Change-Id: Ibaf705367db98beb0e01bb2c3087126cf2ba73e8
Signed-off-by: Deva Ramasubramanian <dramasub@codeaurora.org>
Signed-off-by: Praveen Chavan <pchavan@codeaurora.org>