selftests/bpf: fix compiling loop{1, 2, 3}.c on s390

Use PT_REGS_RC(ctx) instead of ctx->rax, which is not present on s390.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Tested-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
3 files changed