btrfs: btrfs_inode_log_parent should use defined inode_only values.

Replace hardcoded numeric argument values for inode_only with the
constants defined for that use.

Signed-off-by: Edmund Nadolski <enadolski@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>