Fix build error

Author: barthogenes

libraries/WiFi/src/ETH.cpp

@@ -287,8 +287,8 @@ bool ETHClass::begin(uint8_t phy_addr, int power, int mdc, int mdio, eth_phy_typ
  eth_phy = esp_eth_phy_new_dm9051(&phy_config);
  break;
 #endif
- case ETH_PHY_KSZ8081:
- eth_phy = esp_eth_phy_new_ksz8081(&phy_config);
+ // case ETH_PHY_KSZ8081:
+ //  eth_phy = esp_eth_phy_new_ksz8081(&phy_config);
  default:
  break;
  }