ls: handle -d and -R through option_mask32

ls: handle -d and -R through option_mask32

function                                             old     new   delta
scan_and_display_dirs_recur                          545     550      +5
display_single                                      1039    1044      +5
append_char                                           67      68      +1
display_files                                        399     396      -3
ls_main                                              736     717     -19
opt_flags                                             68      11     -57
.rodata                                           168864  168784     -80
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/4 up/down: 11/-159)          Total: -148 bytes

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