media: chips-media: wave5: Fix a hang after seeking

While seeking, the driver calls the flush command. Before the flush
command is sent to the VPU, the driver should handle the display buffer
flags and should get all decoded information from the VPU if the VCORE
is running.

Fixes: 9707a625 ("media: chips-media: wave5: Add the v4l2 layer")
Cc: stable@vger.kernel.org
Signed-off-by: Jackson.lee <jackson.lee@chipsnmedia.com>
Signed-off-by: Nas Chung <nas.chung@chipsnmedia.com>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Sebastian Fricke <sebastian.fricke@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>