net: phy: drop explicit genphy_read_status() op

genphy_read_status() is already the default for the .read_status() op.
Drop the unnecessary references.

Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>