ar71xx: Enable AT803X_PHY to set special flags

ar71xx: Enable AT803X_PHY to set special flags

Open-Mesh OM5P-AN use a AT8035 (F1E) behind one of the ethernet ports. This PHY
requires special flags to work correctly. Otherwise massive packet loss happens
with active POE or when switching the link speed from gigabit ethernet to fast
ethernet. The generic PHY doesn't have support to change these settings.

Signed-off-by: Sven Eckelmann <sven@open-mesh.com>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@45439 3c298f89-4303-0410-b956-a3cf2f4a3e73