Change '#if INET' and '#if INET6' to '#ifdef INET' and '#ifdef INET6'.

This unbreaks compiling a kernel with FAST_IPSEC and no INET6.

sys/netipsec/ipsec.c

@@ -1842,12 +1842,12 @@ char *
 ipsec_address(union sockaddr_union* sa)
 {
 	switch (sa->sa.sa_family) {
-#if INET
+#ifdef INET
 	case AF_INET:
 		return inet_ntoa4(sa->sin.sin_addr);
 #endif /* INET */
 
-#if INET6
+#ifdef INET6
 	case AF_INET6:
 		return ip6_sprintf(&sa->sin6.sin6_addr);
 #endif /* INET6 */

sys/netipsec/ipsec_input.c

@@ -365,7 +365,7 @@ ipsec4_common_input_cb(struct mbuf *m, struct secasvar *sav,
 			goto bad;
 		}
 	}
-#if INET6
+#ifdef INET6
 	/* IPv6-in-IP encapsulation. */
 	if (prot == IPPROTO_IPV6) {
 		struct ip6_hdr ip6n;