selftests/bpf: Remove not used headers

selftests/bpf: Remove not used headers

The following three uapi headers:

    tools/arch/arm64/include/uapi/asm/bpf_perf_event.h
    tools/arch/s390/include/uapi/asm/bpf_perf_event.h
    tools/arch/s390/include/uapi/asm/ptrace.h

were introduced in commit 618e165b2a8e ("selftests/bpf: sync kernel headers
and introduce arch support in Makefile"), they are not used any more after
commit 720f228e8d31 ("bpf: fix broken BPF selftest build"), so remove them.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Link: https://lore.kernel.org/r/1676533861-27508-1-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>