ARM: dts: imx6qp: Specify imx6qp version of PCIe core

I.MX6Quad Plus has a slightly different version of PCIe core than reqular
i.MX6Quad.
Tested-by: Gary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>

arch/arm/boot/dts/imx6qp.dtsi

@@ -82,5 +82,8 @@ ipu2: ipu@02800000 {
 				      "ldb_di0", "ldb_di1", "prg";
 		};
 
+		pcie: pcie@0x01000000 {
+			compatible = "fsl,imx6qp-pcie", "snps,dw-pcie";
+		};
 	};
 };