gif(4) remove bridge(4) support

[Martin Pieuchot]

bridge(4) no longer accept gif(4) interfaces, so kill no dead code, ok?

Index: net/if_gif.c
===================================================================
RCS file: /cvs/src/sys/net/if_gif.c,v
retrieving revision 1.85
diff -u -p -r1.85 if_gif.c
--- net/if_gif.c        13 Apr 2016 11:41:15 -0000      1.85
+++ net/if_gif.c        12 Sep 2016 11:32:03 -0000
@@ -62,8 +62,7 @@
 #include <net/bpf.h>
 #endif
 
-#include "bridge.h"
-#if NBRIDGE > 0 || defined(MPLS)
+#ifdef MPLS
 #include <netinet/ip_ether.h>
 #endif
 
@@ -681,10 +680,6 @@ in_gif_output(struct ifnet *ifp, int fam
        case AF_INET6:
                break;
 #endif
-#if NBRIDGE > 0
-       case AF_LINK:
-               break;
-#endif
 #if MPLS
        case AF_MPLS:
                break;
@@ -700,11 +695,6 @@ in_gif_output(struct ifnet *ifp, int fam
 
        /* encapsulate into IPv4 packet */
        *m0 = NULL;
-#if NBRIDGE > 0
-       if (family == AF_LINK)
-               error = etherip_output(m, &tdb, m0, IPPROTO_ETHERIP);
-       else
-#endif /* NBRIDGE */
 #ifdef MPLS
        if (family == AF_MPLS)
                error = etherip_output(m, &tdb, m0, IPPROTO_MPLS);
@@ -819,10 +809,6 @@ in6_gif_output(struct ifnet *ifp, int fa
        case AF_INET6:
                break;
 #endif
-#if NBRIDGE > 0
-       case AF_LINK:
-               break;
-#endif
 #ifdef MPLS
        case AF_MPLS:
                break;
@@ -838,11 +824,6 @@ in6_gif_output(struct ifnet *ifp, int fa
 
        /* encapsulate into IPv6 packet */
        *m0 = NULL;
-#if NBRIDGE > 0
-       if (family == AF_LINK)
-               error = etherip_output(m, &tdb, m0, IPPROTO_ETHERIP);
-       else
-#endif /* NBRIDGE */
 #if MPLS
        if (family == AF_MPLS)
                error = etherip_output(m, &tdb, m0, IPPROTO_MPLS);