fsck: do not use statics

fsck: do not use statics

function                                             old     new   delta
fsck_main                                           1794    1812     +18
packed_usage                                       30662   30664      +2
kill_all_if_got_signal                                60      62      +2
create_fs_device                                     158     160      +2
static.kill_sent                                       1       -      -1
skip_root                                              1       -      -1
serialize                                              1       -      -1
parallel_root                                          1       -      -1
noexecute                                              1       -      -1
fs_type_negated                                        1       -      -1
force_all_parallel                                     1       -      -1
verbose                                                4       -      -4
num_running                                            4       -      -4
num_args                                               4       -      -4
max_running                                            4       -      -4
instance_list                                          4       -      -4
fstype                                                 4       -      -4
fs_type_list                                           4       -      -4
fs_type_flag                                           4       -      -4
filesys_last                                           4       -      -4
filesys_info                                           4       -      -4
args                                                   4       -      -4
wait_one                                             309     300      -9
ignore                                               196     174     -22
------------------------------------------------------------------------------
(add/remove: 0/18 grow/shrink: 4/2 up/down: 24/-82)           Total: -58 bytes
   text    data     bss     dec     hex filename
 938527     932   17448  956907   e99eb busybox_old
 938487     932   17392  956811   e998b busybox_unstripped

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