using the special tag in this way lead to port mirroring for certain types of traffic.
fallback to using th PMAC_EWAN register for the wan portmap.
Signed-off-by: John Crispin <blogic@openwrt.org>
git-svn-id: svn://svn.openwrt.org/openwrt/branches/chaos_calmer@48086 3c298f89-4303-0410-b956-a3cf2f4a3e73