functions are used to write 1st and 2nd dump_bitmap of kdump-compressed format,
which is used to indicate whether the corresponded page is existed in vmcore.
1st and 2nd dump_bitmap are same, because dump level is specified to 1 here.

Signed-off-by: Qiao Nuohan <qiaonuohan@cn.fujitsu.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>