libbpf: Use correct return pointer in attach_raw_tp

We need to pass '*link' to final libbpf_get_error,
because that one holds the return value, not 'link'.

Fixes: 4fa5bcfe ("libbpf: Allow BPF program auto-attach handlers to bail out")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221114145257.882322-1-jolsa@kernel.org

tools/lib/bpf/libbpf.c

@@ -11169,7 +11169,7 @@ static int attach_raw_tp(const struct bpf_program *prog, long cookie, struct bpf
 	}
 
 	*link = bpf_program__attach_raw_tracepoint(prog, tp_name);
-	return libbpf_get_error(link);
+	return libbpf_get_error(*link);
 }
 
 /* Common logic for all BPF program types that attach to a btf_id */