net: phy: remove flag PHY_HAS_INTERRUPT from driver configs

Now that flag PHY_HAS_INTERRUPT has been replaced with a check for
callbacks config_intr and ack_interrupt, we can remove setting this
flag from all driver configs.
Last but not least remove flag PHY_HAS_INTERRUPT completely.

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