drm: omapdrm: Remove manual update display support

All the manual update display code implements eventually ends up to just
calls to omap_connector_flush(), currently implemented as an empty TODO
stub. Remove it, the code can always be revived and implemented later if
interest in manual update displays becomes a reality.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

diff --cc drivers/gpu/drm/omapdrm/omap_connector.c
Simple merge

diff --cc drivers/gpu/drm/omapdrm/omap_drv.h
Simple merge

diff --cc drivers/gpu/drm/omapdrm/omap_fb.c
Simple merge

diff --cc drivers/gpu/drm/omapdrm/omap_fbdev.c
Simple merge

diff --cc drivers/gpu/drm/omapdrm/omap_plane.c
Simple merge