arm64: dts: rockchip: correct ep-gpios for rk3399-sapphire

The endpoint control gpio for rk3399-sapphire boards is gpio2_a4,
so correct it now.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3399-sapphire.dtsi

@@ -457,7 +457,7 @@ &pcie0 {
 	assigned-clocks = <&cru SCLK_PCIEPHY_REF>;
 	assigned-clock-parents = <&cru SCLK_PCIEPHY_REF100M>;
 	assigned-clock-rates = <100000000>;
-	ep-gpios = <&gpio3 RK_PB5 GPIO_ACTIVE_HIGH>;
+	ep-gpios = <&gpio2 RK_PA4 GPIO_ACTIVE_HIGH>;
 	num-lanes = <4>;
 	pinctrl-names = "default";
 	pinctrl-0 = <&pcie_clkreqn_cpm>;