bpf: Add missing NOP stubs

This fixes kernel build with nodevice bpf [1].

[1] https://lists.freebsd.org/archives/freebsd-current/2023-February/003178.html

Reported by:	Gary Jennejohn <garyj@gmx.de>
Reviewed by:	jhibbits
Fixes:		950cc1f44f bpf: Add "_if" tap APIs
Differential Revision:	https://reviews.freebsd.org/D38432

sys/net/bpf.c

@@ -3120,16 +3120,31 @@ bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen)
 {
 }
 
+void
+bpf_tap_if(if_t ifp, u_char *pkt, u_int pktlen)
+{
+}
+
 void
 bpf_mtap(struct bpf_if *bp, struct mbuf *m)
 {
 }
 
+void
+bpf_mtap_if(if_t ifp, struct mbuf *m)
+{
+}
+
 void
 bpf_mtap2(struct bpf_if *bp, void *d, u_int l, struct mbuf *m)
 {
 }
 
+void
+bpf_mtap2_if(if_t ifp, void *data, u_int dlen, struct mbuf *m)
+{
+}
+
 void
 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen)
 {