msm: vidc: Introducing CBR_CFR upto 720p@30fps

Introducing CBR_CFR (CBR = constant bitrate, CFR = constant framerate
) upto 720p@30fps due to tighter bitrate convergence.

Change-Id: Ic6423a5dfa7df5116f450368021cb5cdb4e09aeb
Signed-off-by: Tapas Kumar Kundu <tkundu@codeaurora.org>