MAINTAINERS: resume as Documentation maintainer

I am the new kernel tree Documentation maintainer (except for parts that
are handled by other people, of course).
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Rob Landley <rob@landley.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS

@@ -2801,9 +2801,9 @@ S:	Supported
 F:	drivers/acpi/dock.c
 
 DOCUMENTATION
-M:	Rob Landley <rob@landley.net>
+M:	Randy Dunlap <rdunlap@infradead.org>
 L:	linux-doc@vger.kernel.org
-T:	TBD
+T:	quilt http://www.infradead.org/~rdunlap/Doc/patches/
 S:	Maintained
 F:	Documentation/