drbd: need include for bitops functions declarations

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c
index b62dd5f..f0ae63d 100644
--- a/drivers/block/drbd/drbd_bitmap.c
+++ b/drivers/block/drbd/drbd_bitmap.c
@@ -28,6 +28,9 @@
 #include <linux/drbd.h>
 #include <linux/slab.h>
 #include <asm/kmap_types.h>
+
+#include <asm-generic/bitops/le.h>
+
 #include "drbd_int.h"