linux-imx

drm/rockchip: prepare common code for cdns and rk dpi/dp driver

- Extracted common fields from cdn_dp_device to a new cdns_mhdp_device
  structure which will be used by two separate drivers later on.
- Moved some datatypes (audio_format, audio_info,
  vic_pxl_encoding_format, video_info) from cdn-dp-core.c to cdn-dp-reg.h.
- Changed prefixes from cdn_dp to cdns_mhdp cdn -> cdns to match the other Cadence's drivers
  dp -> mhdp to distinguish it from a "just a DP" as the IP underneath this registers map can be a HDMI (which is
  internally different, but the interface for commands, events is pretty much the same).
- Modified cdn-dp-core.c to use the new driver structure and new function names.

Signed-off-by: Damian Kos<dkos@cadence.com>
Reviewed-by: Andrzej Hajda<a.hajda@samsung.com>
Signed-off-by: Sandor Yu <Sandor.yu@nxp.com>