net: phy: realtek: add rtl822x_c45_get_features() to set supported port

Sets ETHTOOL_LINK_MODE_TP_BIT in phydev->supported.

Signed-off-by: Eric Woudstra <ericwouds@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>