sched_setaffinity01: use ltp_syscall

Using glibc wrapper on kernel with smaller CONFIG_NR_CPUS (for example
255) leads to segmentation fault in glibc, because it triggers check,
which is verifying that there are no bits set beyond size of kernel cpu
mask:

int
__sched_setaffinity_new (pid_t pid, size_t cpusetsize, const cpu_set_t *cpuset)
  ...
  /* We now know the size of the kernel cpumask_t.  Make sure the user
     does not request to set a bit beyond that.  */
  for (size_t cnt = __kernel_cpumask_size; cnt < cpusetsize; ++cnt)
    if (((char *) cpuset)[cnt] != '\0') --> CRASH HERE

Call this syscall directly with ltp_syscall().

Reported-by: Xiaoguang Wang <wangxg.fnst@cn.fujitsu.com>
Signed-off-by: Jan Stancek <jstancek@redhat.com>
Acked-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Acked-by: Stanislav Kholmanskikh <stanislav.kholmanskikh@oracle.com>