drbd: Move string function prototypes from linux/drbd.h to drbd_string.h

Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 7293ea5..0840e9c 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -45,6 +45,7 @@
 #include <linux/prefetch.h>
 #include <linux/drbd_genl_api.h>
 #include <linux/drbd.h>
+#include "drbd_strings.h"
 #include "drbd_state.h"
 #include "drbd_protocol.h"