s390/tape: add fallthrough annotations

Commit a035d552a9 ("Makefile: Globally enable fall-through warning")
enables fall-through warnings globally. Add missing annotations.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

drivers/s390/char/tape_core.c

@@ -677,6 +677,7 @@ tape_generic_remove(struct ccw_device *cdev)
 	switch (device->tape_state) {
 		case TS_INIT:
 			tape_state_set(device, TS_NOT_OPER);
+			/* fallthrough */
 		case TS_NOT_OPER:
 			/*
 			 * Nothing to do.
@@ -949,6 +950,7 @@ __tape_start_request(struct tape_device *device, struct tape_request *request)
 				break;
 			if (device->tape_state == TS_UNUSED)
 				break;
+			/* fallthrough */
 		default:
 			if (device->tape_state == TS_BLKUSE)
 				break;
@@ -1116,6 +1118,7 @@ __tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
 			case -ETIMEDOUT:
 				DBF_LH(1, "(%08x): Request timed out\n",
 				       device->cdev_id);
+				/* fallthrough */
 			case -EIO:
 				__tape_end_request(device, request, -EIO);
 				break;