drm/bridge: imx: Add i.MX8qm/qxp display pixel link support

This patch adds a drm bridge driver for i.MX8qm/qxp display pixel link.
The pixel link forms a standard asynchronous linkage between
pixel sources(display controller or camera module) and pixel
consumers(imaging or displays).  It consists of two distinct
functions, a pixel transfer function and a control interface.

Reviewed-by: Robert Foss <robert.foss@linaro.org>
Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com> # Colibri iMX8X, LT170410-2WHC, LP156WF1
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/20220611141421.718743-7-victor.liu@nxp.com