drm: kill drm_map_ofs callbacks

All drivers happily copy&pasted the default implementation without
checking whether this callback is used at all. It's not. Sigh.

Kill it.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/i810/i810_drv.c

@@ -52,7 +52,6 @@ static struct drm_driver driver = {
 	.device_is_agp = i810_driver_device_is_agp,
 	.reclaim_buffers_locked = i810_driver_reclaim_buffers_locked,
 	.dma_quiescent = i810_driver_dma_quiescent,
-	.get_map_ofs = drm_core_get_map_ofs,
 	.get_reg_ofs = drm_core_get_reg_ofs,
 	.ioctls = i810_ioctls,
 	.fops = {