media: hantro: Support format filtering by depth

In preparation for supporting 10-bit formats, add mechanism which will
filter formats based on pixel depth.

Hantro G2 supports only one decoding format natively and that is based
on bit depth of current video frame. Additionally, it makes no sense to
upconvert bitness, so filter those out too.

Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Tested-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>