media: amphion: reset instance if it's aborted before codec header parsed

there is hardware limitation that if it's aborted before
the first codec header parsed, the codec may be stalled
unless we do reset codec.

and drop the source change event if it's triggered after reset.

Fixes: 6de8d628 ("media: amphion: add v4l2 m2m vpu decoder stateful driver")
Signed-off-by: Ming Qian <ming.qian@nxp.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>