bpf: fix lsm_cgroup build errors on esoteric configs

This particular ones is about having the following:
CONFIG_BPF_LSM=y
# CONFIG_CGROUP_BPF is not set

Also, add __maybe_unused to the args for the !CONFIG_NET cases.

Reported-by: kernel test robot <[e-mail]>
Signed-off-by: Stanislav Fomichev <[e-mail]>
Acked-by: Yonghong Song <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexei Starovoitov <[e-mail]>

kernel/bpf/bpf_lsm.c

···
 BTF_ID(func, bpf_lsm_socket_socketpair)
 BTF_SET_END(bpf_lsm_unlocked_sockopt_hooks)
 
+#ifdef CONFIG_CGROUP_BPF
 void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog,
 			     bpf_func_t *bpf_func)
 {
-	const struct btf_param *args;
+	const struct btf_param *args __maybe_unused;
 
 	if (btf_type_vlen(prog->aux->attach_func_proto) < 1 ||
 	    btf_id_set_contains(&bpf_lsm_current_hooks,
···
 		return;
 	}
 
+#ifdef CONFIG_NET
 	args = btf_params(prog->aux->attach_func_proto);
 
-#ifdef CONFIG_NET
 	if (args[0].type == btf_sock_ids[BTF_SOCK_TYPE_SOCKET])
 		*bpf_func = __cgroup_bpf_run_lsm_socket;
 	else if (args[0].type == btf_sock_ids[BTF_SOCK_TYPE_SOCK])
···
 #endif
 		*bpf_func = __cgroup_bpf_run_lsm_current;
 }
+#endif
 
 int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
 			const struct bpf_prog *prog)
···
 	case BPF_FUNC_get_retval:
 		return prog->expected_attach_type == BPF_LSM_CGROUP ?
 			&bpf_get_retval_proto : NULL;
+#ifdef CONFIG_NET
 	case BPF_FUNC_setsockopt:
 		if (prog->expected_attach_type != BPF_LSM_CGROUP)
 			return NULL;
···
 					prog->aux->attach_btf_id))
 			return &bpf_unlocked_sk_getsockopt_proto;
 		return NULL;
+#endif
 	default:
 		return tracing_prog_func_proto(func_id, prog);
 	}

kernel/bpf/trampoline.c

···
 	return err;
 }
 
-#if defined(CONFIG_BPF_JIT) && defined(CONFIG_BPF_SYSCALL)
+#if defined(CONFIG_CGROUP_BPF) && defined(CONFIG_BPF_LSM)
 static void bpf_shim_tramp_link_release(struct bpf_link *link)
 {
 	struct bpf_shim_tramp_link *shim_link =