write-ifcfg: do't write MTU twice for regular eth devices

If MTU is specified, we write it for every type of device in the
beginning. There is not point writing it again for Type=ethernet
devices.

modules.d/45ifcfg/write-ifcfg.sh

@@ -201,10 +201,7 @@ for netup in /tmp/net.*.did-setup ; do
     # bridge needs different things written to ifcfg
     if [ -z "$bridge" ] && [ -z "$bond" ] && [ -z "$vlan" ]; then
         # standard interface
-        {
-            echo "TYPE=Ethernet"
-            [ -n "$mtu" ] && echo "MTU=\"$mtu\""
-        } >> /tmp/ifcfg/ifcfg-$netif
+        echo "TYPE=Ethernet" >> /tmp/ifcfg/ifcfg-$netif
     fi
 
     if [ -n "$vlan" ] ; then