netifd: fix a segfault and improve ipip6 tunnel setup

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@40821 3c298f89-4303-0410-b956-a3cf2f4a3e73
Add kernel support for MAP-E FMRs

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@40822 3c298f89-4303-0410-b956-a3cf2f4a3e73
Initial support for MAP-E and Lightweight 4over6 protocol

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@40823 3c298f89-4303-0410-b956-a3cf2f4a3e73