arm64: dts: ti: Move default UART4 RTS GPIO to common board DTSI

When an interaction overlay is loaded after a base overlay, its
inclusion of k3-am623-pfc-rs485.dtsi overrides the baseboard-specific
UART4 rts-gpios config back to GPIO0_38. Moving the default rts-gpios to
the base common DTSI prevents this override, letting the active baseboard
overlay (like p0004224 which uses GPIO0_37) cleanly configure its
specific RTS routing.

Signed-off-by: Heinrich Toews <ht@twx-software.de>

arch/arm64/boot/dts/ti/k3-am623-pfc-750-8xxx-common.dtsi

@@ -286,6 +286,7 @@
 	status = "okay";
 	pinctrl-names = "default";
 	pinctrl-0 = <&main_uart4_pins_default>;
+	rts-gpios = <&main_gpio0 38 GPIO_ACTIVE_HIGH>;
 };
 
 &main_i2c0 { /* type label */

arch/arm64/boot/dts/ti/k3-am623-pfc-rs485.dtsi

@@ -32,7 +32,6 @@
 };
 
 &main_uart4 { /* RS485 Interface */
-	rts-gpios = <&main_gpio0 38 GPIO_ACTIVE_HIGH>;
 	/* RS485 termination is controlled via GPIO userspace tools */
 	rs485-rts-active-high;
 	linux,rs485-enabled-at-boot-time;