of: fix unnecessary warning on missing /cpus node

Not all DT platforms have all the cpus collected under a /cpus node.
That just happens to be a details of FDT, ePAPR and PowerPC platforms.
Sparc does something different, but unfortunately the current code
complains with a warning if /cpus isn't there. This became a problem
with commit f86e4718, "driver/core cpu: initialize of_node in cpu's
device structure", which caused the function to get called for all
architectures.

This commit is a temporary fix to fail silently if the cpus node isn't
present. A proper fix will come later to allow arch code to provide a
custom mechanism for decoding the CPU hwid if the 'reg' property isn't
appropriate.

Signed-off-by: Grant Likely <grant.likely@linaro.org>
Cc: David Miller <davem@davemloft.net>
Cc: Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>
Cc: Rob Herring <rob.herring@calxeda.com>

drivers/of/base.c

@@ -303,10 +303,8 @@ struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
 	struct device_node *cpun, *cpus;
 
 	cpus = of_find_node_by_path("/cpus");
-	if (!cpus) {
-		pr_warn("Missing cpus node, bailing out\n");
+	if (!cpus)
 		return NULL;
-	}
 
 	for_each_child_of_node(cpus, cpun) {
 		if (of_node_cmp(cpun->type, "cpu"))