btrfs: remove pointless comment from ctree.h

It's pointless to have a comment above the prototype declarations of
btrfs_ctree_init() and btrfs_ctree_exit() mentioning that they are
declared in ctree.c. This is from the old days when ctree.h was used
to place anything that didn't fit in any other file. So remove it.

Reviewed-by: Qu Wenruo <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: Filipe Manana <[email protected]>

fs/btrfs/ctree.h

@@ -505,7 +505,6 @@ static inline u32 BTRFS_MAX_XATTR_SIZE(const struct btrfs_fs_info *info)
 	return BTRFS_MAX_ITEM_SIZE(info) - sizeof(struct btrfs_dir_item);
 }
 
-/* ctree.c */
 int __init btrfs_ctree_init(void);
 void __cold btrfs_ctree_exit(void);