bpftool: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK

We have switched to memcg-based memory accouting and thus the rlimit is
not needed any more. LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK was introduced in
libbpf for backward compatibility, so we can use it instead now.

libbpf_set_strict_mode always return 0, so we don't need to check whether
the return value is 0 or not.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220409125958.92629-4-laoar.shao@gmail.com

tools/bpf/bpftool/struct_ops.c

@@ -501,8 +501,6 @@ static int do_register(int argc, char **argv)
 	if (libbpf_get_error(obj))
 		return -1;
 
-	set_max_rlimit();
-
 	if (bpf_object__load(obj)) {
 		bpf_object__close(obj);
 		return -1;