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 <baruch@tkos.co.il>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/platforms/xtfpga/setup.c

@@ -168,7 +168,7 @@ void __init platform_calibrate_ccount(void)
 	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);