Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/scsi/ch.c b/drivers/scsi/ch.c
index 1c5051b..76751d6 100644
--- a/drivers/scsi/ch.c
+++ b/drivers/scsi/ch.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * SCSI Media Changer device driver for Linux 2.6
  *
@@ -578,7 +579,6 @@
 	scsi_changer *ch = file->private_data;
 
 	scsi_device_put(ch->device);
-	ch->device = NULL;
 	file->private_data = NULL;
 	kref_put(&ch->ref, ch_destroy);
 	return 0;