Currently, the network interfaces that are not configured by the bootloader
(using e.g. tftp or ping) can detect the link status but are unable to
transmit data.

The network controller has a functionality that allows the hardware to
continuously poll the PHY and directly update the MAC configuration accordingly
(speed, duplex, etc.). However, this doesn't work well with phylib's
software-based polling and updating MAC configuration in the driver's callback.

This commit fixes this issue by:

  1. Setting MVPP2_PHY_AN_STOP_SMI0_MASK in MVPP2_PHY_AN_CFG0_REG in
     mvpp2_init(), which disables the harware polling feature.

  2. Disabling MVPP2_GMAC_PCS_ENABLE_MASK bit in MVPP2_GMAC_CTRL_2_REG in
     mvpp2_port_mii_set() for port types other than SGMII.
Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Signed-off-by: David S. Miller <davem@davemloft.net>