selftests/bpf: Add tracing_struct test in DENYLIST.s390x

Add tracing_struct test in DENYLIST.s390x since s390x does not
support trampoline now.

Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220831152723.2081551-1-yhs@fb.com


Signed-off-by: Alexei Starovoitov <ast@kernel.org>