arm64: dts: rockchip: Add UART9 M0 pin definitions to rk3588s

This is used on Orange Pi 5 Plus.
Signed-off-by: Ondrej Jirman <megi@xff.cz>
Link: https://lore.kernel.org/r/20231008130515.1155664-3-megi@xff.czSigned-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3588s-pinctrl.dtsi

@@ -3342,6 +3342,15 @@ uart8_xfer: uart8-xfer {
 	};
 
 	uart9 {
+		/omit-if-no-ref/
+		uart9m0_xfer: uart9m0-xfer {
+			rockchip,pins =
+				/* uart9_rx_m0 */
+				<2 RK_PC4 10 &pcfg_pull_up>,
+				/* uart9_tx_m0 */
+				<2 RK_PC2 10 &pcfg_pull_up>;
+		};
+
 		/omit-if-no-ref/
 		uart9m1_xfer: uart9m1-xfer {
 			rockchip,pins =