drm/bridge: imx: Add i.MX8qxp pixel link to DPI support

This patch adds a drm bridge driver for i.MX8qxp pixel link to display
pixel interface(PXL2DPI).  The PXL2DPI interfaces the pixel link 36-bit
data output and the DSI controller’s MIPI-DPI 24-bit data input, and
inputs of LVDS Display Bridge(LDB) module used in LVDS mode, to remap
the pixel color codings between those modules. The PXL2DPI is purely
combinatorial.

Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com> # Colibri iMX8X, LT170410-2WHC, LP156WF1
Reviewed-by: Robert Foss <robert.foss@linaro.org>
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/20220611141421.718743-9-victor.liu@nxp.com