powerpc/pseries: Fix node leak in update_lmb_associativity_index()

In update_lmb_associativity_index() we lookup dr_node using
of_find_node_by_path() which takes a reference for us. In the
non-error case we forget to drop the reference. Note that
find_aa_index() does modify properties of the node, but doesn't need
an extra reference held once it's returned.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/pseries/hotplug-memory.c

@@ -197,6 +197,7 @@ static int update_lmb_associativity_index(struct drmem_lmb *lmb)
 
 	found = find_aa_index(dr_node, ala_prop, lmb_assoc, &aa_index);
 
+	of_node_put(dr_node);
 	dlpar_free_cc_nodes(lmb_node);
 
 	if (!found) {