du: remove statics (by Bernhard Fischer <rep.dot.nop@gmail.com>)

du: remove statics (by Bernhard Fischer <rep.dot.nop@gmail.com>)

$ ./.cmk bloatcheck
function                                             old     new   delta
du_main                                              340     348      +8
print                                                 39      40      +1
status                                               129     125      -4
slink_depth                                            4       -      -4
print_files                                            4       -      -4
one_file_system                                        4       -      -4
max_print_depth                                        4       -      -4
du_depth                                               4       -      -4
disp_hr                                                4       -      -4
count_hardlinks                                        4       -      -4
du                                                   407     401      -6
dir_dev                                                8       -      -8
------------------------------------------------------------------------------
(add/remove: 0/8 grow/shrink: 2/2 up/down: 9/-46)             Total: -37 bytes
   text    data     bss     dec     hex filename
    864      12      28     904     388 busybox.t3/coreutils/du.o
    867       0       0     867     363 busybox.t4/coreutils/du.o
 770647    1063   10788  782498   bf0a2 busybox.t3/busybox_unstripped
 770651    1051   10764  782466   bf082 busybox.t4/busybox_unstripped