drm: bridge: Add Chipone ICN6211 MIPI-DSI to RGB bridge

ICN6211 is MIPI-DSI to RGB Converter bridge from Chipone.

It has a flexible configuration of MIPI DSI signal input and
produce RGB565, RGB666, RGB888 output format.

Add bridge driver for it.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210322103328.66442-2-jagan@amarulasolutions.com