drm: core changes broke i810/830

Reported by Joseph Fannin during -mm, revert incorrect change.
Signed-off-by: Dave Airlie <airlied@linux.ie>

drivers/char/drm/i810_drv.c

@@ -112,7 +112,7 @@ static struct drm_driver driver = {
 		.open = drm_open,
 		.release = drm_release,
 		.ioctl = drm_ioctl,
-		.mmap = i810_mmap_buffers,
+		.mmap = drm_mmap,
 		.poll = drm_poll,
 		.fasync = drm_fasync,
 	},

drivers/char/drm/i830_drv.c

@@ -121,7 +121,7 @@ static struct drm_driver driver = {
 		.open = drm_open,
 		.release = drm_release,
 		.ioctl = drm_ioctl,
-		.mmap = i830_mmap_buffers,
+		.mmap = drm_mmap,
 		.poll = drm_poll,
 		.fasync = drm_fasync,
 	},