cpumask: remove x86 cpumask_t uses.

Impact: cleanup

We are removing cpumask_t in favour of struct cpumask: mainly as a
marker of what code is now CONFIG_CPUMASK_OFFSTACK-safe.

The only non-trivial change here is vector_allocation_domain():
explicitly clear the mask and set the first word, rather than using
assignment.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

arch/x86/mm/numa_64.c

@@ -697,7 +697,7 @@ void __cpuinit numa_remove_cpu(int cpu)
 static void __cpuinit numa_set_cpumask(int cpu, int enable)
 {
 	int node = early_cpu_to_node(cpu);
-	cpumask_t *mask;
+	struct cpumask *mask;
 	char buf[64];
 
 	mask = node_to_cpumask_map[node];