bcm54213: Probe PHY address 0x01 and 0x00

The PHY address was fixed at 0x01 before. Because the CM4 uses the
different address 0x00, it is probed now, if reading the MII_BMSR
register fails with address 0x01. In this case address 0x00 is used,
if reading MII_BMSR succeeds with it.