powerpc/powermac/pfunc_core.c: Add of_node_put to avoid memory leak

Add a call to of_node_put in the error handling code following a call to
of_find_node_by_phandle.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r exists@
local idexpression x;
expression E,E1;
statement S;
@@

*x =
(of_find_node_by_path
|of_find_node_by_name
|of_find_node_by_phandle
|of_get_parent
|of_get_next_parent
|of_get_next_child
|of_find_compatible_node
|of_match_node
)(...);
...
if (x == NULL) S
<... when != x = E
*if (...) {
  ... when != of_node_put(x)
      when != if (...) { ... of_node_put(x); ... }
(
  return <+...x...+>;
|
*  return ...;
)
}
...>
of_node_put(x);
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powermac/pfunc_core.c

@@ -837,8 +837,10 @@ struct pmf_function *__pmf_find_function(struct device_node *target,
 		return NULL;
  find_it:
 	dev = pmf_find_device(actor);
-	if (dev == NULL)
-		return NULL;
+	if (dev == NULL) {
+		result = NULL;
+		goto out;
+	}
 
 	list_for_each_entry(func, &dev->functions, link) {
 		if (name && strcmp(name, func->name))
@@ -850,8 +852,9 @@ struct pmf_function *__pmf_find_function(struct device_node *target,
 		result = func;
 		break;
 	}
-	of_node_put(actor);
 	pmf_put_device(dev);
+out:
+	of_node_put(actor);
 	return result;
 }