media: docs: Add some RGB bus formats for i.MX8qm/qxp pixel combiner

media: docs: Add some RGB bus formats for i.MX8qm/qxp pixel combiner

This patch adds documentations for RGB666_1X30_CPADLO, RGB888_1X30_CPADLO,
RGB666_1X36_CPADLO and RGB888_1X36_CPADLO bus formats used by i.MX8qm/qxp
pixel combiner.  The RGB pixels with padding low per component are
transmitted on a 30-bit input bus(10-bit per component) from a display
controller or a 36-bit output bus(12-bit per component) to a pixel link.

Reviewed-by: Robert Foss <robert.foss@linaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220611141421.718743-3-victor.liu@nxp.com