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

tools/testing/selftests/bpf/DENYLIST.s390x

@@ -70,3 +70,4 @@ setget_sockopt                           # attach unexpected error: -524
 cb_refs                                  # expected error message unexpected error: -524                               (trampoline)
 cgroup_hierarchical_stats                # JIT does not support calling kernel function                                (kfunc)
 htab_update                              # failed to attach: ERROR: strerror_r(-524)=22                                (trampoline)
+tracing_struct                           # failed to auto-attach: -524                                                 (trampoline)