hwc: Add support for smooth streaming feature.

Update the source video width and height set by the video decoder
for the secure video smooth streaming usecase from the gralloc
metadata.

Change-Id: I73a3804d90557034604142481a232787dbc08f23
Acked-by: Ramkumar Radhakrishnan <ramkumar@codeaurora.org>
Signed-off-by: Lajos Molnar <lajos@google.com>
Bug: 9533458