media: dt-bindings: media: sun6i: Add A31 and H3 compatibles

The H3 has a slightly different CSI controller (no BT656, no CCI) which
looks a lot like the original A31 controller. Add a compatible for the A31,
and more specific compatible the for the H3 to be used in combination for
the A31.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>