powerpc/powernv: 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>
@@
local idexpression n;
expression e;
@@

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

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1448051604-25256-4-git-send-email-Julia.Lawall@lip6.fr

arch/powerpc/platforms/powernv/opal-lpc.c

@@ -396,6 +396,7 @@ void __init opal_lpc_init(void)
 		if (!of_get_property(np, "primary", NULL))
 			continue;
 		opal_lpc_chip_id = of_get_ibm_chip_id(np);
+		of_node_put(np);
 		break;
 	}
 	if (opal_lpc_chip_id < 0)