arm64: dts: ti: k3-j721s2: 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/20240124184722.150615-8-afd@ti.comSigned-off-by: Vignesh Raghavendra <vigneshr@ti.com>

arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi

@@ -58,11 +58,11 @@ phy_gmii_sel_cpsw: phy@34 {
 		};
 
 		serdes_ln_ctrl: mux-controller@80 {
-			compatible = "mmio-mux";
+			compatible = "reg-mux";
 			reg = <0x80 0x10>;
 			#mux-control-cells = <1>;
-			mux-reg-masks = <0x80 0x3>, <0x84 0x3>, /* SERDES0 lane0/1 select */
-					<0x88 0x3>, <0x8c 0x3>; /* SERDES0 lane2/3 select */
+			mux-reg-masks = <0x0 0x3>, <0x4 0x3>, /* SERDES0 lane0/1 select */
+					<0x8 0x3>, <0xc 0x3>; /* SERDES0 lane2/3 select */
 		};
 
 		ehrpwm_tbclk: clock-controller@140 {