s390/qdio: use QDIO_BUFNR()

qdio.h recently gained a new helper macro that handles wrap-around on a
QDIO queue, use it.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
1 file changed