debugfs: mark me as the maintainer

Add DEBUGFS information to my MAINTAINERS entry as some people have
asked about this recently.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

MAINTAINERS

@@ -2050,14 +2050,16 @@ F:	drivers/block/drbd/
 F:	lib/lru_cache.c
 F:	Documentation/blockdev/drbd/
 
-DRIVER CORE, KOBJECTS, AND SYSFS
+DRIVER CORE, KOBJECTS, DEBUGFS AND SYSFS
 M:	Greg Kroah-Hartman <gregkh@suse.de>
 T:	quilt kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/
 S:	Supported
 F:	Documentation/kobject.txt
 F:	drivers/base/
 F:	fs/sysfs/
+F:	fs/debugfs/
 F:	include/linux/kobj*
+F:	include/linux/debugfs.h
 F:	lib/kobj*
 
 DRM DRIVERS