net: phy: switch drivers to use dynamic feature detection

Recently genphy_read_abilities() has been added that dynamically detects
clause 22 PHY abilities. I *think* this detection should work with all
supported PHY's, at least for the ones with basic features sets, i.e.
PHY_BASIC_FEATURES and PHY_GBIT_FEATURES. So let's remove setting these
features explicitly and rely on phylib feature detection.

I don't have access to most of these PHY's, therefore I'd appreciate
regression testing.

v2:
- make the feature constant a comment so that readers know which
  features are supported by the respective PHY

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

drivers/net/phy/amd.c

@@ -60,7 +60,7 @@ static struct phy_driver am79c_driver[] = { {
 	.phy_id		= PHY_ID_AM79C874,
 	.name		= "AM79C874",
 	.phy_id_mask	= 0xfffffff0,
-	.features	= PHY_BASIC_FEATURES,
+	/* PHY_BASIC_FEATURES */
 	.config_init	= am79c_config_init,
 	.ack_interrupt	= am79c_ack_interrupt,
 	.config_intr	= am79c_config_intr,