drm/imx: Add i.MX8qxp Display Controller display engine

drm/imx: Add i.MX8qxp Display Controller display engine

i.MX8qxp Display Controller display engine consists of all processing
units that operate in a display clock domain.  Add minimal feature
support with FrameGen and TCon so that the engine can output display
timings.  The FrameGen driver, TCon driver and display engine driver
are components to be aggregated by a master registered in the upcoming
DRM driver.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20250414035028.1561475-10-victor.liu@nxp.com