CPE510: Add ROUTERMAC

This adds missing ROUTERMAC variable for CPE510

Signed-off-by: Fabian Bläse <fabian@blaese.de>
Reviewed-by: Christian Dresel <fff@chrisi01.de>

src/packages/fff/fff-network/ar71xx/network.cpe510

@@ -12,6 +12,7 @@ BATMAN_PORTS="0t"
 # only possible, because wXmesh is created first and therefore gets the 'universally administered address'
 
 ETHMESHMAC=$(macFlipLocalBit "$(cat /sys/class/ieee80211/phy0/macaddress)")
+ROUTERMAC=$(cat /sys/class/net/eth0/address)
 
 . /etc/network.mode