tools headers: Remove s390 ptrace.h in check-headers.sh

After commit 1f265d2aea0dff1f ("selftests/bpf: Remove not used headers"),
tools/arch/s390/include/uapi/asm/ptrace.h has been removed, so remove
it in check-headers.sh too, otherwise we can see the following build
warning:

diff: tools/arch/s390/include/uapi/asm/ptrace.h: No such file or directory

Fixes: 1f265d2aea0dff1f ("selftests/bpf: Remove not used headers")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: bpf@vger.kernel.org
Cc: loongson-kernel@lists.loongnix.cn
Link: https://lore.kernel.org/oe-kbuild-all/202304050029.38NdbQPf-lkp@intel.com/
Link: https://lore.kernel.org/r/1680834090-2322-1-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>