MAINTAINERS: Add file patterns for net device tree bindings

Submitters of device tree binding documentation may forget to CC
the subsystem maintainer if this is missing.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -7832,6 +7832,7 @@ Q:	http://patchwork.ozlabs.org/project/netdev/list/
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git
 S:	Odd Fixes
+F:	Documentation/devicetree/bindings/net/
 F:	drivers/net/
 F:	include/linux/if_*
 F:	include/linux/netdevice.h