arm64: dts: rockchip: add PCIe for M.2 M-key to rock-5b

The Radxa Rock 5B has PCIe 3x4 routed to its M.2 M-key connector
on the board's back.
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20230918141451.131247-3-sebastian.reichel@collabora.comSigned-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3588-rock-5b.dts

@@ -53,6 +53,19 @@ vcc3v3_pcie2x1l2: vcc3v3-pcie2x1l2-regulator {
 		vin-supply = <&vcc_3v3_s3>;
 	};
 
+	vcc3v3_pcie30: vcc3v3-pcie30-regulator {
+		compatible = "regulator-fixed";
+		enable-active-high;
+		gpios = <&gpio1 RK_PA4 GPIO_ACTIVE_HIGH>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&pcie3_vcc3v3_en>;
+		regulator-name = "vcc3v3_pcie30";
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+		startup-delay-us = <5000>;
+		vin-supply = <&vcc5v0_sys>;
+	};
+
 	vcc5v0_host: vcc5v0-host-regulator {
 		compatible = "regulator-fixed";
 		regulator-name = "vcc5v0_host";
@@ -225,6 +238,18 @@ &pcie2x1l2 {
 	status = "okay";
 };
 
+&pcie30phy {
+	status = "okay";
+};
+
+&pcie3x4 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pcie3_rst>;
+	reset-gpios = <&gpio4 RK_PB6 GPIO_ACTIVE_HIGH>;
+	vpcie3v3-supply = <&vcc3v3_pcie30>;
+	status = "okay";
+};
+
 &pinctrl {
 	hym8563 {
 		hym8563_int: hym8563-int {
@@ -244,6 +269,16 @@ pcie2_2_rst: pcie2-2-rst {
 		};
 	};
 
+	pcie3 {
+		pcie3_rst: pcie3-rst {
+			rockchip,pins = <4 RK_PB6 RK_FUNC_GPIO &pcfg_pull_none>;
+		};
+
+		pcie3_vcc3v3_en: pcie3-vcc3v3-en {
+			rockchip,pins = <1 RK_PA4 RK_FUNC_GPIO &pcfg_pull_none>;
+		};
+	};
+
 	usb {
 		vcc5v0_host_en: vcc5v0-host-en {
 			rockchip,pins = <4 RK_PB0 RK_FUNC_GPIO &pcfg_pull_none>;