msm: vidc: Set dpb count based on target for smooth streaming

The min_dpb required for smooth streaming is set for the
max requirement of 1080p playback session. For 8960 num
of dpb required is 18 and for 8660 it is 8. This is set
in vidc platform data in the resepective device file.

Change-Id: I1e6bc3e8dcd64a00a7eb159f4600d40f5c229e45
Signed-off-by: Mohan Kumar Gubbihalli Lachma Naik <mgubbi@codeaurora.org>