UdpNtpClient example: removed wrong return type

libraries/Ethernet/examples/UdpNtpClient/UdpNtpClient.ino

@@ -109,7 +109,7 @@ void loop() {
 }
 
 // send an NTP request to the time server at the given address
-unsigned long sendNTPpacket(char* address) {
+void sendNTPpacket(char* address) {
   // set all bytes in the buffer to 0
   memset(packetBuffer, 0, NTP_PACKET_SIZE);
   // Initialize values needed to form NTP request