v4l2_stateful_decoder: Teach MDP to also increase |displayed_frames|

write_frame_to_disk() relies on the queue's |displayed_frames|
to know the index of the YUV file to write. This CL increases
that when appropriate.

BUG=b:180615056
TEST=emerge+deploy+v4l2_stateful_decoder ... --mmap  -w
on Hana and TAL at the individual yuv files.

Change-Id: I55d1eedf2eb9576fba1fb1572ad09a276f2b5d25
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/drm-tests/+/3262760
Tested-by: Miguel Casas <mcasas@chromium.org>
Commit-Queue: Miguel Casas <mcasas@chromium.org>
Reviewed-by: Nathan Hebert <nhebert@chromium.org>
1 file changed