Add a flag and helper function to indicate that a PHY device is part of
an SFP module, which is set on attach. This can be used by PHY drivers
to handle SFP-specific quirks or behavior.
Signed-off-by: NRobert Hancock <robert.hancock@calian.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>