s390/char: use for_each_clear_bit()

Use for_each_clear_bit() to iterate over all the cleared bit in a
memory region.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/s390/char/sclp_cmd.c

@@ -441,9 +441,8 @@ static int sclp_mem_notifier(struct notifier_block *nb,
 	start = arg->start_pfn << PAGE_SHIFT;
 	size = arg->nr_pages << PAGE_SHIFT;
 	mutex_lock(&sclp_mem_mutex);
-	for (id = 0; id <= sclp_max_storage_id; id++)
-		if (!test_bit(id, sclp_storage_ids))
-			sclp_attach_storage(id);
+	for_each_clear_bit(id, sclp_storage_ids, sclp_max_storage_id + 1)
+		sclp_attach_storage(id);
 	switch (action) {
 	case MEM_ONLINE:
 	case MEM_GOING_OFFLINE: