powerpc: Use call_rcu_sched() for pagetables

PowerPC relies on IRQ-disable to guard against RCU quiecent states,
use the appropriate RCU call version.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/mm/pgtable.c

@@ -92,7 +92,7 @@ static void pte_free_rcu_callback(struct rcu_head *head)
 
 static void pte_free_submit(struct pte_freelist_batch *batch)
 {
-	call_rcu(&batch->rcu, pte_free_rcu_callback);
+	call_rcu_sched(&batch->rcu, pte_free_rcu_callback);
 }
 
 void pgtable_free_tlb(struct mmu_gather *tlb, void *table, unsigned shift)