drm/sysfb: Maintain CRTC state in struct drm_sysfb_crtc_state

Move ofdrm's struct ofdrm_crtc_state plus functions to sysfb
helpers and rename everything to drm_sysfb_crtc_state.

The sysfb CRTC state is a regular CRTC state with information on
the primary plane's color format, as required for color management.
Helpers for sysfb planes will later set this up automatically.

In ofdrm and simpledrm, replace existing code with the new helpers.
Ofdrm continues to use the CRTC state for color management. This
has no effect on simpledrm.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20250401094056.32904-10-tzimmermann@suse.de