powerpc: 4xx: get cpu node with of_get_cpu_node

"device_type" use is deprecated for FDT though it has continued to be used
for nodes like cpu nodes. Use of_get_cpu_node() instead which works using
node names by default. This will allow the eventually removal of cpu
device_type properties.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Rob Herring <robh@kernel.org>

arch/powerpc/platforms/4xx/soc.c

@@ -200,7 +200,7 @@ void ppc4xx_reset_system(char *cmd)
 	u32 reset_type = DBCR0_RST_SYSTEM;
 	const u32 *prop;
 
-	np = of_find_node_by_type(NULL, "cpu");
+	np = of_get_cpu_node(0, NULL);
 	if (np) {
 		prop = of_get_property(np, "reset-type", NULL);