net: phy: genphy_c45_pma_baset1_read_master_slave: read actual configuration

Since MDIO_PMA_PMD_BT1_CTRL register shows actual configuration (and
forced state configuration is equal to the state), we should show
this configuration for ethtool.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>