msm:vidc: Add support for MP2 sequence end code

ISDB-T client requires end of sequence notification
in the flags of the output buffer when sequence end
code is queued to the video core. Add support by reading
from video core shared memory and update the output buffer
flags for MPEG-2 codec.

Change-Id: Idd88fc6a5cdccb41fa61ba902a0014ec8359739a
Signed-off-by: Rajeshwar Kurapaty <rkurapat@codeaurora.org>