s390/tape: add fallthrough annotations

Commit a035d552a93b ("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>
1 file changed