arm64: dts: ti: k3-j7200: Convert serdes_ln_ctrl node into reg-mux

This removes a dependency on the parent node being a syscon node.
Convert from mmio-mux to reg-mux adjusting node name and properties
as needed.
Signed-off-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20240124184722.150615-3-afd@ti.comSigned-off-by: Vignesh Raghavendra <vigneshr@ti.com>

arch/arm64/boot/dts/ti/k3-j7200-main.dtsi

@@ -33,10 +33,11 @@ scm_conf: scm-conf@100000 {
 		ranges = <0x00 0x00 0x00100000 0x1c000>;
 
 		serdes_ln_ctrl: mux-controller@4080 {
-			compatible = "mmio-mux";
+			compatible = "reg-mux";
+			reg = <0x4080 0x20>;
 			#mux-control-cells = <1>;
-			mux-reg-masks = <0x4080 0x3>, <0x4084 0x3>, /* SERDES0 lane0/1 select */
-					<0x4088 0x3>, <0x408c 0x3>; /* SERDES0 lane2/3 select */
+			mux-reg-masks = <0x0 0x3>, <0x4 0x3>, /* SERDES0 lane0/1 select */
+					<0x8 0x3>, <0xc 0x3>; /* SERDES0 lane2/3 select */
 		};
 
 		cpsw0_phy_gmii_sel: phy@4044 {