powerpc/pseries: Add mising of_node_put in delete_dt_node

The node to be detached is retrieved via its phandle by a call to
of_find_node_by_phandle which increments the ref count. We need a matching
call to of_node_put to decrement the ref count and ensure the node is
actually freed.
Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/pseries/mobility.c

@@ -62,6 +62,7 @@ static int delete_dt_node(u32 phandle)
 		return -ENOENT;
 
 	dlpar_detach_node(dn);
+	of_node_put(dn);
 	return 0;
 }