drm: renesas: shmobile: Atomic conversion + DT support
Currently, there are two drivers for the LCD controller on Renesas
SuperH-based and ARM-based SH-Mobile and R-Mobile SoCs:
1. sh_mobile_lcdcfb, using the fbdev framework,
2. shmob_drm, using the DRM framework.
However, only the former driver is used, as all platform support
integrates the former. None of these drivers support DT-based systems.
Convert the SH-Mobile DRM driver to atomic modesetting, and add DT
support, complemented by the customary set of fixes and improvements.