media: dt-bindings: media: i2c: Add mono version to IMX290 bindings

Backport from https://patchwork.linuxtv.org/project/linux-media/list/?series=9918



The IMX290 module is available as either monochrome or colour and
the variant is not detectable at runtime.

Add a new compatible string for the monochrome version, based on the
full device name IMX290LLR. For consistency, add a new compatible string
for the colour version based on the IMX290LQR full device name, and
deprecate the current ambiguous compatible string.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>