Add two missing includes and remove two uneeded.

This is quite serious fix, because even with MAC framework compiled in,
MAC entry points in those two files were simply ignored.

sys/kern/kern_jail.c

@@ -10,12 +10,15 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include "opt_mac.h"
+
 #include <sys/param.h>
 #include <sys/types.h>
 #include <sys/kernel.h>
 #include <sys/systm.h>
 #include <sys/errno.h>
 #include <sys/sysproto.h>
+#include <sys/mac.h>
 #include <sys/malloc.h>
 #include <sys/proc.h>
 #include <sys/taskqueue.h>

sys/net/if_fwsubr.c

@@ -32,10 +32,12 @@
 
 #include "opt_inet.h"
 #include "opt_inet6.h"
+#include "opt_mac.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/kernel.h>
+#include <sys/mac.h>
 #include <sys/malloc.h>
 #include <sys/mbuf.h>
 #include <sys/socket.h>

sys/net/if_loop.c

@@ -38,7 +38,6 @@
 #include "opt_inet.h"
 #include "opt_inet6.h"
 #include "opt_ipx.h"
-#include "opt_mac.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>

sys/netinet/ip_fastfwd.c

@@ -80,7 +80,6 @@
 #include "opt_ipdivert.h"
 #include "opt_ipfilter.h"
 #include "opt_ipstealth.h"
-#include "opt_mac.h"
 #include "opt_pfil_hooks.h"
 
 #include <sys/param.h>