ARM: dts: imx6qp: reference PCIe node by handle

By using the handle, we can avoid some duplication of the base DT
and so avoid any maintenance overhead in the QP DT if the referenced
node changes.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6qp.dtsi

@@ -82,10 +82,6 @@ ipu2: ipu@02800000 {
 				      "ldb_di0", "ldb_di1", "prg";
 		};
 
-		pcie: pcie@0x01000000 {
-			compatible = "fsl,imx6qp-pcie", "snps,dw-pcie";
-		};
-
 		aips-bus@02100000 {
 			mmdc0: mmdc@021b0000 { /* MMDC0 */
 				compatible = "fsl,imx6qp-mmdc", "fsl,imx6q-mmdc";
@@ -110,3 +106,7 @@ &ldb {
 		      "di0_sel", "di1_sel", "di2_sel", "di3_sel",
 		      "di0", "di1";
 };
+
+&pcie {
+	compatible = "fsl,imx6qp-pcie", "snps,dw-pcie";
+};