net: phy: mscc: fix Serdes configuration in vsc8584_config_init

When converting the MSCC PHY driver to shared PHY packages, the Serdes
configuration in vsc8584_config_init was modified to use 'base_addr'
instead of 'base' as the port number. But 'base_addr' isn't equal to
'addr' for all PHYs inside the package, which leads to the Serdes still
being enabled on those ports. This patch fixes it.

Fixes: deb04e9c ("net: phy: mscc: use phy_package_shared")
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>