MAINTAINERS: update DRM DRIVERS patterns

Signed-off-by: NJoe Perches <joe@perches.com>
Cc: David Airlie <airlied@linux.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS

@@ -2019,6 +2019,7 @@ L:	dri-devel@lists.freedesktop.org
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6.git
 S:	Maintained
 F:	drivers/gpu/drm/
+F:	include/drm/
 
 DSCC4 DRIVER
 M:	Francois Romieu <romieu@fr.zoreil.com>