xtensa: standardize devicetree cpu compatible strings

The recommended compatible string format, according to the ePAPR v1.1 standard,
is "manufacturer,model". Change the xtensa cpu compatible strings to
"cdns,xtensa-cpu". Also, change the boards compatible strings in a similar way.

The pic compatible string will be dealt with in a separate patch.

Signed-off-by: Baruch Siach <[e-mail]>
Signed-off-by: Max Filippov <[e-mail]>

arch/xtensa/boot/dts/lx60.dts

···
 /include/ "xtfpga-flash-4m.dtsi"
 
 / {
-	compatible = "xtensa,lx60";
+	compatible = "cdns,xtensa-lx60";
 	memory@0 {
 		device_type = "memory";
 		reg = <0x00000000 0x04000000>;

arch/xtensa/boot/dts/ml605.dts

···
 /include/ "xtfpga-flash-16m.dtsi"
 
 / {
-	compatible = "xtensa,ml605";
+	compatible = "cdns,xtensa-ml605";
 	memory@0 {
 		device_type = "memory";
 		reg = <0x00000000 0x08000000>;

arch/xtensa/boot/dts/xtfpga.dtsi

···
 / {
-	compatible = "xtensa,xtfpga";
+	compatible = "cdns,xtensa-xtfpga";
 	#address-cells = <1>;
 	#size-cells = <1>;
 	interrupt-parent = <&pic>;
···
 		#address-cells = <1>;
 		#size-cells = <0>;
 		cpu@0 {
-			compatible = "xtensa,cpu";
+			compatible = "cdns,xtensa-cpu";
 			reg = <0>;
 			/* Filled in by platform_setup from FPGA register
 			 * clock-frequency = <100000000>;

arch/xtensa/platforms/xtfpga/setup.c

···
 	long clk_freq = 0;
 #ifdef CONFIG_OF
 	struct device_node *cpu =
-		of_find_compatible_node(NULL, NULL, "xtensa,cpu");
+		of_find_compatible_node(NULL, NULL, "cdns,xtensa-cpu");
 	if (cpu) {
 		u32 freq;
 		update_clock_frequency(cpu);