[S390] tape: cleanup reference counting

Rename tape_get_device to tape_find_device and tape_get_device_reference
to tape_get_device. The old names didn't make too much sense.

Follow the get_device()/put_device() semantic and convert tape_put_device
to a void function.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/char/tape_proc.c b/drivers/s390/char/tape_proc.c
index 202f421..ebd820c 100644
--- a/drivers/s390/char/tape_proc.c
+++ b/drivers/s390/char/tape_proc.c
@@ -45,7 +45,7 @@
 		seq_printf(m, "TapeNo\tBusID      CuType/Model\t"
 			"DevType/Model\tBlkSize\tState\tOp\tMedState\n");
 	}
-	device = tape_get_device(n);
+	device = tape_find_device(n);
 	if (IS_ERR(device))
 		return 0;
 	spin_lock_irq(get_ccwdev_lock(device->cdev));