msm: display: plane alpha support

Clean up the blending rule to follow blend_op set from hwc.
Use modulate alpha for plane alpha when it is not 0xff.
Keep backward compatibility if blend_op is not set.

Change-Id: I02fd3c3c7b5ace2e6eec22b2db0284161404a0fc
Signed-off-by: Ken Zhang <kenz@codeaurora.org>
msm: vidc: add support for the bitstream_restrict flag

Adds support for the MFC core to add the bitstream_restrict flag in the
sps/pps for H264 codecs.  This allows for the decoder to determine how
many frames to buffer when decoding.

Change-Id: Ic0de960d92a771d74c303dac7100734d6411fc45
Signed-off-by: Deepak Verma <dverma@codeaurora.org>