media: hantro: Use v4l2_m2m_buf_done_and_job_finish

Let the core sort out the nuances of returning buffers
to userspace, by using the v4l2_m2m_buf_done_and_job_finish
helper.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>