fix(lwip): Initialize len to ensure it's set before check

Author: nitz

Diff for: libraries/Network/src/NetworkUdp.cpp

@@ -296,7 +296,7 @@ int NetworkUDP::parsePacket() {
   }
   struct sockaddr_storage si_other_storage;  // enough storage for v4 and v6
   socklen_t slen = sizeof(sockaddr_storage);
-  int len;
+  int len = 0;
   if (ioctl(udp_server, FIONREAD, &len) == -1) {
     log_e("could not check for data in buffer length: %d", errno);
     return 0;