reiserfs: cleanup, remove unnecessary parens in dirent creation

make_empty_dir_item_v1 and make_empty_dir_item also needed a bit of cleanup
but it's clearer to use separate pointers rather than the array positions
for just two items.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>