cpufreq: Avoid a bad reference count on CPU node

In the parse_perf_domain function, if the call to
of_parse_phandle_with_args returns an error, then the reference to the
CPU device node that was acquired at the start of the function would not
be properly decremented.

Address this by declaring the variable with the __free(device_node)
cleanup attribute.

Signed-off-by: Miquel Sabaté Solà <[e-mail]>
Acked-by: Viresh Kumar <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Cc: All applicable <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

include/linux/cpufreq.h

···
 				    const char *cell_name,
 				    struct of_phandle_args *args)
 {
-	struct device_node *cpu_np;
 	int ret;
 
-	cpu_np = of_cpu_device_node_get(cpu);
+	struct device_node *cpu_np __free(device_node) = of_cpu_device_node_get(cpu);
 	if (!cpu_np)
 		return -ENODEV;
 
···
 					 args);
 	if (ret < 0)
 		return ret;
-
-	of_node_put(cpu_np);
-
 	return 0;
 }