Recently new modes have been added to ethtool.h, but the related
extension to phylib hasn't been done yet. So add support for these
modes.

v2:
- add missing 100Gbps and 50Gbps modes
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>