ath6kl: add missing of_node_put

for_each_compatible_node performs an of_node_get on each iteration, so
a break out of the loop requires an of_node_put.

A simplified version of the semantic patch that fixes this problem is as
follows (http://coccinelle.lip6.fr):

// <smpl>
@@
expression e;
local idexpression n;
@@

 for_each_compatible_node(n,...) {
   ... when != of_node_put(n)
       when != e = n
(
   return n;
|
+  of_node_put(n);
?  return ...;
)
   ...
 }
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/wireless/ath/ath6kl/init.c

@@ -715,6 +715,7 @@ static bool check_device_tree(struct ath6kl *ar)
 				   board_filename, ret);
 			continue;
 		}
+		of_node_put(node);
 		return true;
 	}
 	return false;