ARM: dts: imx6qdl: Add default GIC address cells

Add missing address-cells 0 to GPC interrupt node to silence W=1
warning:

  imx6qdl.dtsi:281.4-284.29: Warning (interrupt_map): /soc/pcie@1ffc000:interrupt-map:
    Missing property '#address-cells' in node /soc/bus@2000000/gpc@20dc000, using 0 as fallback

Value '0' is correct because:
1. GPC interrupt controller children are only power domains,
2. interrupt-map property (in PCI node) consists of five components and
   the fourth component "parent unit address", which size is defined by
   '#address-cells' of the node pointed to by the interrupt-parent
   component, is not used (=0)

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Author: tq-steina

arch/arm/boot/dts/nxp/imx/imx6qdl.dtsi

@@ -875,6 +875,7 @@
 			gpc: gpc@20dc000 {
 				compatible = "fsl,imx6q-gpc";
 				reg = <0x020dc000 0x4000>;
+				#address-cells = <0>;
 				interrupt-controller;
 				#interrupt-cells = <3>;
 				interrupts = <0 89 IRQ_TYPE_LEVEL_HIGH>;