s390/qdio: fix up tiqdio_thinint_handler() kerneldoc

Missed in commit f4eae94f
("s390/airq: simplify adapter interrupt code")

Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Reviewed-by: Steffen Maier <maier@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>