msm:vidc: Add the support for MPEG-2 extension and user data

Support is added for MPEG-2 extension and user data. With this
changes Core returns extension and user data as an extradata.

Change-Id: Icdb9da359d90799391b5b9751df2e735ff93475e
Signed-off-by: Shobhit Pandey <cshopan@codeaurora.org>