M1: compat layer + pf.ko skeleton builds against Linux 7.3.4

- pfk.h: BSD types/ioctl encoding (OpenBSD bit layout), locks (NET_LOCK=rwsem),
  pools, timeouts, mbuf shim over sk_buff, ifnet registry, toeplitz/siphash
- pfk_mod/pfk_hooks: misc /dev/pf (0600), IPv4 netfilter hook skeleton,
  DIOCGETSTATUS answered (M1 skeleton; engine ioctls land with pf_ioctl.c)
- vendorize/stage-port scripts: deterministic upstream staging with seds
  (struct renames, IFF_*->PFIFF_*, sa_len drops) logged to docs/porting-notes
- fixes: modules_prepare+Module.symvers for out-of-tree builds

scripts/vendorize.sh

@@ -9,8 +9,9 @@ SYS_K=(net/pf.c net/pf_ioctl.c net/pf_norm.c net/pf_if.c net/pf_lb.c net/pf_rule
        net/pf_table.c net/pf_osfp.c net/pf_syncookies.c net/pfvar.h net/pfvar_priv.h
        net/if_pflog.c net/if_pflog.h net/ifq.c net/ifq.h net/hfsc.c net/hfsc.h
        net/fq_codel.c net/fq_codel.h netinet/ip_divert.c netinet/ip_divert.h
-       net/radix.c net/radix.h net/radix_node.h net/rtable.c net/rtable.h
-       sys/tree.h sys/queue.h sys/param.h sys/hash.h)
+       net/radix.c net/radix.h net/rtable.c net/rtable.h net/toeplitz.c net/toeplitz.h
+       crypto/sha2.c crypto/sha2.h crypto/siphash.c crypto/siphash.h
+       sys/tree.h sys/queue.h sys/param.h sys/hash.h sys/_endian.h sys/_lock.h)
 SRC_K=(sbin/pfctl/parse.y sbin/pfctl/pfctl.c sbin/pfctl/pfctl.h sbin/pfctl/pfctl_parser.c
        sbin/pfctl/pfctl_parser.h sbin/pfctl/pfctl_optimize.c sbin/pfctl/pfctl_print.c
        sbin/pfctl/pfctl_osfp.c sbin/pfctl/pfctl_queue.c sbin/pfctl/pfctl_radix.c