btrfs: annotate intentional switch case fallthroughs

This keeps static checkers happy.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>

fs/btrfs/ctree.c

@@ -1138,6 +1138,7 @@ __tree_mod_log_rewind(struct extent_buffer *eb, u64 time_seq,
 		switch (tm->op) {
 		case MOD_LOG_KEY_REMOVE_WHILE_FREEING:
 			BUG_ON(tm->slot < n);
+			/* Fallthrough */
 		case MOD_LOG_KEY_REMOVE_WHILE_MOVING:
 		case MOD_LOG_KEY_REMOVE:
 			btrfs_set_node_key(eb, &tm->key, tm->slot);

fs/btrfs/super.c

@@ -437,6 +437,7 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
 		case Opt_compress_force:
 		case Opt_compress_force_type:
 			compress_force = true;
+			/* Fallthrough */
 		case Opt_compress:
 		case Opt_compress_type:
 			if (token == Opt_compress ||