cpumask: remove cpumask_t from core

Impact: cleanup

struct cpumask is nicer, and we use it to make where we've made code
safe for CONFIG_CPUMASK_OFFSTACK=y.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/kernel/sched_cpupri.h b/kernel/sched_cpupri.h
index 642a94e..9a7e859 100644
--- a/kernel/sched_cpupri.h
+++ b/kernel/sched_cpupri.h
@@ -25,7 +25,7 @@
 
 #ifdef CONFIG_SMP
 int  cpupri_find(struct cpupri *cp,
-		 struct task_struct *p, cpumask_t *lowest_mask);
+		 struct task_struct *p, struct cpumask *lowest_mask);
 void cpupri_set(struct cpupri *cp, int cpu, int pri);
 int cpupri_init(struct cpupri *cp, bool bootmem);
 void cpupri_cleanup(struct cpupri *cp);