btrfs: fix comment about max_out in btrfs_compress_pages

Commit e5d74902 ("btrfs: derive maximum output size in the
compression implementation") removed @max_out argument in
btrfs_compress_pages() but its comment remained, remove it.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/compression.c

@@ -1194,9 +1194,6 @@ static unsigned int btrfs_compress_set_level(int type, unsigned level)
  *
  * @total_out is an in/out parameter, must be set to the input length and will
  * be also used to return the total number of compressed bytes
- *
- * @max_out tells us the max number of bytes that we're allowed to
- * stuff into pages
  */
 int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
 			 u64 start, struct page **pages,