MAINTAINERS: Remove rcar-du.h entry

commit 2378ad12 ("drm: rcar-du: Remove platform data support")
removed the file, remove the pattern.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

MAINTAINERS

@@ -3378,7 +3378,6 @@ T:	git git://people.freedesktop.org/~airlied/linux
 S:	Supported
 F:	drivers/gpu/drm/rcar-du/
 F:	drivers/gpu/drm/shmobile/
-F:	include/linux/platform_data/rcar-du.h
 F:	include/linux/platform_data/shmob_drm.h
 
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