mm-video: vdec: Get updated resolution along with output buffers

In case of smooth streaming the driver width/height might be
be updated multiple times before VIDIOC_G_FMT call was made to
the driver to get first updated width/height itself if the input
sequence has Header(w1xh1), AU data, Header(w2xh2), AU data and so on.
So client need to get the width/height along with output buffer itself
to update the display with correct width/height for every output frame
and skip calling VIDIOC_G_FMT to driver to get width/height.

Change-Id: I31992315a84350ddb7a43577dc70235ad9a8bc8f