ls: code shrink

ls: code shrink

function                                             old     new   delta
list_single                                            -    1006   +1006
print_name                                           211     209      -2
dnalloc                                               15      13      -2
splitdnarray                                         192     189      -3
ls_main                                              848     833     -15
showdirs                                             564     505     -59
showfiles                                           1460     372   -1088
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/6 up/down: 1006/-1169)       Total: -163 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>