msm: vidc: add support for input_tag, input_tag2 and sub-frame info

1. Client needs input etb to output fbd association. Introducing
   input_tag and input_tag2 fields for this. Client will send
   input_tag via etb reserved fields and client will get back
   those as part of fbd reserved fields.
2. Convey sub-frame information to client from firmware.

CRs-Fixed: 2494945

Change-Id: Ic64131c7f8f3e3035cd6ff3997fe483171d71fc4
Signed-off-by: Govindaraj Rajagopal <grajagop@codeaurora.org>