fix UDP builds on nRF (#7394)

* fix UDP builds on nRF
* fix rp2040 too

src/mesh/eth/ethClient.cpp

@@ -68,9 +68,11 @@ static int32_t reconnectETH()
                 initApiServer();
             }
 #endif
+#if HAS_UDP_MULTICAST
             if (udpHandler && config.network.enabled_protocols & meshtastic_Config_NetworkConfig_ProtocolFlags_UDP_BROADCAST) {
                 udpHandler->start();
             }
+#endif
 
             ethStartupComplete = true;
         }

src/platform/nrf52/AsyncUDP.cpp

@@ -1,5 +1,7 @@
 #include "AsyncUDP.h"
 
+#if HAS_ETHERNET
+
 AsyncUDP::AsyncUDP() : OSThread("AsyncUDP"), localPort(0) {}
 
 bool AsyncUDP::listenMulticast(IPAddress multicastIP, uint16_t port, uint8_t ttl)
@@ -67,3 +69,5 @@ int32_t AsyncUDP::runOnce()
     }
     return 5; // check every 5ms
 }
+
+#endif // HAS_ETHERNET

src/platform/nrf52/AsyncUDP.h

@@ -1,6 +1,10 @@
 #ifndef ASYNC_UDP_H
 #define ASYNC_UDP_H
 
+#include "configuration.h"
+
+#if HAS_ETHERNET
+
 #include "concurrency/OSThread.h"
 #include <IPAddress.h>
 #include <Print.h>
@@ -54,4 +58,6 @@ inline bool isMulticast(const IPAddress &ip)
     return (ip[0] & 0xF0) == 0xE0;
 }
 
+#endif // HAS_ETHERNET
+
 #endif // ASYNC_UDP_H