sched: use slab in cpupri_init()

Lets not use the bootmem allocator in cpupri_init() as slab is already up when
it is run.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

kernel/sched.c

@@ -7795,7 +7795,7 @@ static int __init_refok init_rootdomain(struct root_domain *rd, bool bootmem)
 	if (!alloc_cpumask_var(&rd->rto_mask, gfp))
 		goto free_online;
 
-	if (cpupri_init(&rd->cpupri, false) != 0)
+	if (cpupri_init(&rd->cpupri, bootmem) != 0)
 		goto free_rto_mask;
 	return 0;