btrfs: tree-checker: fix incorrect printk format

This patch addresses a compile warning:

fs/btrfs/extent-tree.c: In function '__btrfs_free_extent':
fs/btrfs/extent-tree.c:3187:4: warning: format '%lu' expects argument of type 'long unsigned int', but argument 8 has type 'unsigned int' [-Wformat=]

Fixes: 1c2a07f5 ("btrfs: extent-tree: kill BUG_ON() in __btrfs_free_extent()")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Pujin Shi <shipujin.t@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent-tree.c

@@ -3185,7 +3185,7 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
 		struct btrfs_tree_block_info *bi;
 		if (item_size < sizeof(*ei) + sizeof(*bi)) {
 			btrfs_crit(info,
-"invalid extent item size for key (%llu, %u, %llu) owner %llu, has %u expect >= %lu",
+"invalid extent item size for key (%llu, %u, %llu) owner %llu, has %u expect >= %zu",
 				   key.objectid, key.type, key.offset,
 				   owner_objectid, item_size,
 				   sizeof(*ei) + sizeof(*bi));