net: fix build errors if ipv6 is disabled

CONFIG_IPV6=n is still a valid choice ;)

It appears we can remove dead code.

Reported-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/security/lsm_audit.c b/security/lsm_audit.c
index 80554fc..234bc2a 100644
--- a/security/lsm_audit.c
+++ b/security/lsm_audit.c
@@ -302,6 +302,7 @@
 						"faddr", "fport");
 				break;
 			}
+#if IS_ENABLED(CONFIG_IPV6)
 			case AF_INET6: {
 				struct inet_sock *inet = inet_sk(sk);
 
@@ -313,6 +314,7 @@
 						"faddr", "fport");
 				break;
 			}
+#endif
 			case AF_UNIX:
 				u = unix_sk(sk);
 				if (u->path.dentry) {