net: dsa: lantiq_gswip: Enable GSWIP_MII_CFG_EN also for internal PHYs

net: dsa: lantiq_gswip: Enable GSWIP_MII_CFG_EN also for internal PHYs

[ Upstream commit c1a9ec7e5d577a9391660800c806c53287fca991 ]

Enable GSWIP_MII_CFG_EN also for internal PHYs to make traffic flow.
Without this the PHY link is detected properly and ethtool statistics
for TX are increasing but there's no RX traffic coming in.

Fixes: 14fceff4771e51 ("net: dsa: Add Lantiq / Intel DSA driver for vrx200")
Suggested-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>