s390/cio: Use BITS_TO_LONGS() instead of __BITOPS_WORDS()

Use BITS_TO_LONGS() instead of __BITOPS_WORDS() that is considered
to be private macro in asm/bitops.h for s390.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/idset.c

@@ -17,7 +17,7 @@ struct idset {
 
 static inline unsigned long bitmap_size(int num_ssid, int num_id)
 {
-	return __BITOPS_WORDS(num_ssid * num_id) * sizeof(unsigned long);
+	return BITS_TO_LONGS(num_ssid * num_id) * sizeof(unsigned long);
 }
 
 static struct idset *idset_new(int num_ssid, int num_id)