ARM: dts: am572x-idk: Add gpios property to control PCIE_RESETn

Add 'gpios' property to pcie1 dt node and populate it with
GPIO3_23 in order to drive PCIE_RESETn high.

This gets PCIe cards to be detected in AM572X IDK board.
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/am572x-idk.dts

@@ -87,3 +87,7 @@ &mmc1 {
 &sn65hvs882 {
 	load-gpios = <&gpio3 19 GPIO_ACTIVE_LOW>;
 };
+
+&pcie1 {
+	gpios = <&gpio3 23 GPIO_ACTIVE_HIGH>;
+};