s390/numa: use correct type for node_to_cpumask_map

With CONFIG_CPUMASK_OFFSTACK=y cpumask_var_t is a pointer to a CPU mask.
Replace the incorrect type for node_to_cpumask_map with cpumask_t.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/topology.h b/arch/s390/include/asm/topology.h
index 27ebde6..94fc55f 100644
--- a/arch/s390/include/asm/topology.h
+++ b/arch/s390/include/asm/topology.h
@@ -68,7 +68,7 @@
 #define cpumask_of_node cpumask_of_node
 static inline const struct cpumask *cpumask_of_node(int node)
 {
-	return node_to_cpumask_map[node];
+	return &node_to_cpumask_map[node];
 }
 
 /*