Patch allows to configure the mtu of the dynamic 6rd tunnel interface when created by dhcp script.
In some setups it's desirable to have config control over the 6rd tunnel mtu to maximize the traffic throughput
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@42871 3c298f89-4303-0410-b956-a3cf2f4a3e73