Fix ETH not enabling DHCP when configured with INADDR_NONE

Fixes: espressif#4778

Author: me-no-dev

libraries/WiFi/src/ETH.cpp

@@ -118,7 +118,7 @@ bool ETHClass::config(IPAddress local_ip, IPAddress gateway, IPAddress subnet, I
  esp_err_t err = ESP_OK;
  tcpip_adapter_ip_info_t info;
 
- if(local_ip != (uint32_t)0x00000000){
+ if(local_ip != (uint32_t)0x00000000 && local_ip != INADDR_NONE){
  info.ip.addr = static_cast<uint32_t>(local_ip);
  info.gw.addr = static_cast<uint32_t>(gateway);
  info.netmask.addr = static_cast<uint32_t>(subnet);
@@ -153,13 +153,13 @@ bool ETHClass::config(IPAddress local_ip, IPAddress gateway, IPAddress subnet, I
  ip_addr_t d;
  d.type = IPADDR_TYPE_V4;
 
- if(dns1 != (uint32_t)0x00000000) {
+ if(dns1 != (uint32_t)0x00000000 && dns1 != INADDR_NONE) {
  // Set DNS1-Server
  d.u_addr.ip4.addr = static_cast<uint32_t>(dns1);
  dns_setserver(0, &d);
  }
 
- if(dns2 != (uint32_t)0x00000000) {
+ if(dns2 != (uint32_t)0x00000000 && dns2 != INADDR_NONE) {
  // Set DNS2-Server
  d.u_addr.ip4.addr = static_cast<uint32_t>(dns2);
  dns_setserver(1, &d);