arm64: dts: ti: k3-j721s2-common-proc-board: Add uart pinmux

Define the wakeup uart pin-mux for completeness and add explicit
muxing for mcu_uart0. This allows the device tree usage in bootloader
and firmwares that can configure the same appropriately.
Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Udit Kumar <u-kumar1@ti.com>
Link: https://lore.kernel.org/r/20230602153554.1571128-6-nm@ti.comSigned-off-by: Vignesh Raghavendra <vigneshr@ti.com>

arch/arm64/boot/dts/ti/k3-j721s2-common-proc-board.dts

@@ -155,6 +155,24 @@ J721S2_IOPAD(0x0ec, PIN_OUTPUT, 6) /* (AG25) TIMER_IO1.USB0_DRVVBUS */
 };
 
 &wkup_pmx2 {
+	wkup_uart0_pins_default: wkup-uart0-pins-default {
+		pinctrl-single,pins = <
+			J721S2_WKUP_IOPAD(0x070, PIN_INPUT, 0) /* (E25) WKUP_GPIO0_6.WKUP_UART0_CTSn */
+			J721S2_WKUP_IOPAD(0x074, PIN_OUTPUT, 0) /* (F28) WKUP_GPIO0_7.WKUP_UART0_RTSn */
+			J721S2_WKUP_IOPAD(0x048, PIN_INPUT, 0) /* (D28) WKUP_UART0_RXD */
+			J721S2_WKUP_IOPAD(0x04c, PIN_OUTPUT, 0) /* (D27) WKUP_UART0_TXD */
+		>;
+	};
+
+	mcu_uart0_pins_default: mcu-uart0-pins-default {
+		pinctrl-single,pins = <
+			J721S2_WKUP_IOPAD(0x090, PIN_INPUT, 0) /* (B24) WKUP_GPIO0_14.MCU_UART0_CTSn */
+			J721S2_WKUP_IOPAD(0x094, PIN_OUTPUT, 0) /* (D25) WKUP_GPIO0_15.MCU_UART0_RTSn */
+			J721S2_WKUP_IOPAD(0x08c, PIN_INPUT, 0) /* (C24) WKUP_GPIO0_13.MCU_UART0_RXD */
+			J721S2_WKUP_IOPAD(0x088, PIN_OUTPUT, 0) /* (C25) WKUP_GPIO0_12.MCU_UART0_TXD */
+		>;
+	};
+
 	mcu_cpsw_pins_default: mcu-cpsw-pins-default {
 		pinctrl-single,pins = <
 			J721S2_WKUP_IOPAD(0x02c, PIN_INPUT, 0) /* (B22) MCU_RGMII1_RD0 */
@@ -265,11 +283,14 @@ &wkup_gpio1 {
 
 &wkup_uart0 {
 	status = "reserved";
+	pinctrl-names = "default";
+	pinctrl-0 = <&wkup_uart0_pins_default>;
 };
 
 &mcu_uart0 {
 	status = "okay";
-	/* Default pinmux */
+	pinctrl-names = "default";
+	pinctrl-0 = <&mcu_uart0_pins_default>;
 };
 
 &main_uart8 {