bpf, selftests: Use raw_tp program for atomic test

Now atomic tests will attach fentry program and run it through
bpf_prog_test_run_opts(), but attaching fentry program depends on BPF
trampoline which is only available under x86-64. Considering many archs
have atomic support, using raw_tp program instead.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220217072232.1186625-5-houtao1@huawei.com