cpumask: Replace cpu_coregroup_map with cpu_coregroup_mask

cpu_coregroup_map returned a cpumask_t: it's going away.

(Note, the sched part of this patch won't apply meaningfully to the
sched tree, but I'm posting it to show the goal).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ingo Molnar <mingo@redhat.com>

block/blk.h

@@ -99,8 +99,8 @@ static inline int queue_congestion_off_threshold(struct request_queue *q)
 static inline int blk_cpu_to_group(int cpu)
 {
 #ifdef CONFIG_SCHED_MC
-	cpumask_t mask = cpu_coregroup_map(cpu);
-	return first_cpu(mask);
+	const struct cpumask *mask = cpu_coregroup_mask(cpu);
+	return cpumask_first(mask);
 #elif defined(CONFIG_SCHED_SMT)
 	return first_cpu(per_cpu(cpu_sibling_map, cpu));
 #else