media: i.MX6: Support 16-bit BT.1120 video input

Confirmed to work with ADV7610 HDMI receiver.

Signed-off-by: Krzysztof Hałasa <khalasa@piap.pl>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>