drm: fixup kerneldoc in drm_crtc.h

drm: fixup kerneldoc in drm_crtc.h

I've tried to cc all the people who have recently added new stuff
but forgotten to update documentation.

I've also decided not to bother documenting the massive property list
in struct drm_mode_config. If that beast keeps on growing we might want
to extract it into a separate structure which we won't document.

Cc: Thomas Wood <thomas.wood@intel.com>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>