media: dt-bindings: media: i2c: Add bindings for TW9900

The Techwell TW9900 is a video decoder supporting multiple input
standards such as PAL and NTSC and has a parallel BT.656 output
interface.

It's designed to be low-power, posesses some features such as a
programmable comb-filter, and automatic input standard detection

Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mehdi Djait <mehdi.djait@bootlin.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>