syscalls/adjtimex01.c: cleanup

cleanup for syscalls/adjtimex01.c

Signed-off-by: DAN LI <li.dan@cn.fujitsu.com>
Reviewed-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
syscalls/adjtimex01.c: Test for mode ADJ_OFFSET_SINGLESHOT

Additional test for mode ADJ_OFFSET_SINGLESHOT.

Signed-off-by: DAN LI <li.dan@cn.fujitsu.com>
Reviewed-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>