bpftool: use new API for attaching XDP program

Switch to new bpf_xdp_attach() API to avoid deprecation warnings.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220120061422.2710637-3-andrii@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

tools/bpf/bpftool/net.c

@@ -551,7 +551,7 @@ static int do_attach_detach_xdp(int progfd, enum net_attach_type attach_type,
 	if (attach_type == NET_ATTACH_TYPE_XDP_OFFLOAD)
 		flags |= XDP_FLAGS_HW_MODE;
 
-	return bpf_set_link_xdp_fd(ifindex, progfd, flags);
+	return bpf_xdp_attach(ifindex, progfd, flags, NULL);
 }
 
 static int do_attach(int argc, char **argv)