s390/qdio: allow to scan all 128 Input SBALs

The comment is inaccurate, qdio_inbound_q_moved() and/or its callers no
longer get confused by a count of 128 completed SBALs.

Scanning all 128 SBALs at once can improve IRQ reduction (as we now
place the ACK at the right spot), and reduce the amount of processing
needed to handle all completed SBALs.
Signed-off-by: NJulian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: NHeiko Carstens <hca@linux.ibm.com>

drivers/s390/cio/qdio_main.c

@@ -457,11 +457,7 @@ static int get_inbound_buffer_frontier(struct qdio_q *q, unsigned int start)
 
 	q->timestamp = get_tod_clock_fast();
 
-	/*
-	 * Don't check 128 buffers, as otherwise qdio_inbound_q_moved
-	 * would return 0.
-	 */
-	count = min(atomic_read(&q->nr_buf_used), QDIO_MAX_BUFFERS_MASK);
+	count = atomic_read(&q->nr_buf_used);
 	if (!count)
 		return 0;