ar8031: modify the config func of ar8031 to ar8021_config

ar8031 has the same config steps with ar8021, so change its
config func to ar8021_config instead of genphy_config.

Signed-off-by: Zhao Qiang <B45475@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>

drivers/net/phy/atheros.c

@@ -53,7 +53,7 @@ static struct phy_driver AR8031_driver =  {
 	.uid = 0x4dd074,
 	.mask = 0xffffffef,
 	.features = PHY_GBIT_FEATURES,
-	.config = genphy_config,
+	.config = ar8021_config,
 	.startup = genphy_startup,
 	.shutdown = genphy_shutdown,
 };