msm: vidc: Add support to request frame bits info as extra-data

Provides information regarding number of bits in the frame (i.e frame
size expressed in bits) & also the number of bits in frame header (i.e
frame header size expressed in bits).
Number of bits in header is reported as:
For H264, sum of all slice headers bits for all the slices in the frame.
For all other codecs, number of bits in the frame header.

Change-Id: I6caeca025ff0ce059a20891a6d657b47c4b452b3
Signed-off-by: Jorge Solano Altamirano <jsolano@codeaurora.org>