MAINTAINERS: Add devicetree binding to PCI i.MX6 entry

Add an entry for the devicetree binding file, so that when people run
./scripts/get_maintainer.pl the PCI imx6 maintainers could also be listed.
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Lucas Stach <l.stach@pengutronix.de>

MAINTAINERS

@@ -9235,6 +9235,7 @@ M:	Lucas Stach <l.stach@pengutronix.de>
 L:	linux-pci@vger.kernel.org
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 S:	Maintained
+F:	Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.txt
 F:	drivers/pci/host/*imx6*
 
 PCI DRIVER FOR TI KEYSTONE