net: phy: replace bool members in struct phy_device with bit-fields

In struct phy_device we have a number of flags being defined as type
bool. Similar to e.g. struct pci_dev we can save some space by using
bit-fields.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>