[S390] Improve AP bus device removal.

Added a call to device_unregister() in ap_scan_bus() to actively
remove unavailable AP bus devices with every bus scan. Previously
devices were only removed in ap_queue_message() or __ap_poll_all().
Signed-off-by: Ralph Wuerthner <rwuerthn@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/crypto/ap_bus.c

@@ -739,11 +739,16 @@ static void ap_scan_bus(void *data)
 		dev = bus_find_device(&ap_bus_type, NULL,
 				      (void *)(unsigned long)qid,
 				      __ap_scan_bus);
+		rc = ap_query_queue(qid, &queue_depth, &device_type);
+		if (dev && rc) {
+			put_device(dev);
+			device_unregister(dev);
+			continue;
+		}
 		if (dev) {
 			put_device(dev);
 			continue;
 		}
-		rc = ap_query_queue(qid, &queue_depth, &device_type);
 		if (rc)
 			continue;
 		rc = ap_init_queue(qid);