arm64: dts: ti: k3-*: Convert DMSS to simple-bus

"simple-mfd" as standalone compatible is frowned upon, so model DMSS
(Data Movement Subsystem) node as simple-bus as there is really no need
for these nodes to be MFD.

Link: https://lore.kernel.org/r/20231005151302.1290363-2-vigneshr@ti.com
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>

arch/arm64/boot/dts/ti/k3-am62-main.dtsi

@@ -82,7 +82,7 @@
 
 	dmss: bus@48000000 {
 		bootph-all;
-		compatible = "simple-mfd";
+		compatible = "simple-bus";
 		#address-cells = <2>;
 		#size-cells = <2>;
 		dma-ranges;

arch/arm64/boot/dts/ti/k3-am62p-main.dtsi

@@ -42,7 +42,7 @@
 
 	dmss: bus@48000000 {
 		bootph-all;
-		compatible = "simple-mfd";
+		compatible = "simple-bus";
 		#address-cells = <2>;
 		#size-cells = <2>;
 		dma-ranges;

arch/arm64/boot/dts/ti/k3-am64-main.dtsi

@@ -99,7 +99,7 @@
 
 	dmss: bus@48000000 {
 		bootph-all;
-		compatible = "simple-mfd";
+		compatible = "simple-bus";
 		#address-cells = <2>;
 		#size-cells = <2>;
 		dma-ranges;