cpumask: convert node_to_cpumask_map[] to cpumask_var_t

Impact: reduce kernel memory usage when CONFIG_CPUMASK_OFFSTACK=y

Straightforward conversion: done for 32 and 64 bit kernels.
node_to_cpumask_map is now a cpumask_var_t array.

64-bit used to be a dynamic cpumask_t array, and 32-bit used to be a
static cpumask_t array.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index dc31d92..f8b833e 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -86,15 +86,15 @@
 #endif /* CONFIG_X86_64 */
 
 /* Mappings between node number and cpus on that node. */
-extern cpumask_t *node_to_cpumask_map;
+extern cpumask_var_t node_to_cpumask_map[MAX_NUMNODES];
 
 #ifdef CONFIG_DEBUG_PER_CPU_MAPS
 extern const cpumask_t *cpumask_of_node(int node);
 #else
 /* Returns a pointer to the cpumask of CPUs on Node 'node'. */
-static inline const cpumask_t *cpumask_of_node(int node)
+static inline const struct cpumask *cpumask_of_node(int node)
 {
-	return &node_to_cpumask_map[node];
+	return node_to_cpumask_map[node];
 }
 #endif