util/ioctl: cut vain check on GetIfaceMaxHWHeaderLength

src/util-ioctl.c

@@ -139,10 +139,6 @@ int GetIfaceMaxPacketSize(const char *pcap_dev)
             return 0;
     }
     int ll_header = GetIfaceMaxHWHeaderLength(pcap_dev);
-    if (ll_header == -1) {
-        /* be conservative, choose a big one */
-        ll_header = 16;
-    }
     return ll_header + mtu;
 }