lantiq: dm200: Fix loading PHY firmware

lantiq: dm200: Fix loading PHY firmware

The device has 1 100MBit/s port. By default the PHY firmware is running
in 1GBit/s mode. The driver will try to load the 1GBit/s firmware and
fail if it is not there. Set the GPHY0 also to 100MBit/s mode.

The driver uses all nodes independent of the status attribute.

Do the same fix for AVM FRITZ!Box 7412 too.

Reported-by: Achelon in OpenWrt forum
Fixes: https://github.com/openwrt/openwrt/issues/21836
Link: https://github.com/openwrt/openwrt/pull/22188
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>