vidc: Use PMEM in case of encoder input buffers

Change-Id: Ibe28b2e72c1611b12a7217f719a169feb0dacedf
msm_serial_hs_ti: Cleanup & add back comments

HTC is known for stripping all the comments in their kernels
Restored comments from msm_serial_hs based on 89443dc3f74ff0e45a4c1fee096d576a082bef69

Also added back some code to bring up-to-date with the original msm_serial_hs driver

Change-Id: I0f5cbf3d775a2e93accd369b6394cfb184fe6023