Fix mac address display

iftop would display portions of mac address with large ffffff prefixes.
Make if_hw_addr type consistent.  Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>

addrs_ioctl.c

@@ -45,7 +45,7 @@
  */
 
 int
-get_addrs_ioctl(char *interface, char if_hw_addr[], struct in_addr *if_ip_addr, struct in6_addr *if_ip6_addr)
+get_addrs_ioctl(char *interface, u_int8_t if_hw_addr[], struct in_addr *if_ip_addr, struct in6_addr *if_ip6_addr)
 {
   int s;
   struct ifreq ifr = {};