cpumask: Use accessors for cpu_*_mask: um

Use the accessors rather than frobbing bits directly (the new versions
are const).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
diff --git a/arch/um/kernel/smp.c b/arch/um/kernel/smp.c
index 98351c7..106bf27 100644
--- a/arch/um/kernel/smp.c
+++ b/arch/um/kernel/smp.c
@@ -111,7 +111,7 @@
 	int i;
 
 	for (i = 0; i < ncpus; ++i)
-		cpu_set(i, cpu_possible_map);
+		set_cpu_possible(i, true);
 
 	cpu_clear(me, cpu_online_map);
 	cpu_set(me, cpu_online_map);