msm: vidc: Adds support for VP8 Decoder.

Adds support for VP8 Decoder by adding VP8 codec
entry in vdec formats struct.

Change-Id: I93bca63e18ae2ba2a125e76584d230c0af1cc33a
Signed-off-by: Praneeth Paladugu <ppaladug@codeaurora.org>