dm vdo: remove bad check of bi_next field

Remove this check to prevent spurious warning messages due to
the behavior of other storage layers. This check was intended
to make sure dm-vdo does not chain metadata bios together.
However, vdo has no control over underlying storage layers,
so the assertion is not always true.
Signed-off-by: Ken Raeburn <raeburn@redhat.com>
Signed-off-by: Matthew Sakai <msakai@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

drivers/md/dm-vdo/io-submitter.c

@@ -346,7 +346,6 @@ void __submit_metadata_vio(struct vio *vio, physical_block_number_t physical,
 
 
 	VDO_ASSERT_LOG_ONLY(!code->quiescent, "I/O not allowed in state %s", code->name);
-	VDO_ASSERT_LOG_ONLY(vio->bio->bi_next == NULL, "metadata bio has no next bio");
 
 	vdo_reset_completion(completion);
 	completion->error_handler = error_handler;