change int to unsigned int in IRrecvDumpV2

some larger values could overflow to negative numbers, with unsigned int (vs int)

Author: AnalysIR

examples/IRrecvDumpV2/IRrecvDumpV2.ino

@@ -95,7 +95,7 @@ void  dumpRaw (decode_results *results)
   Serial.print("     -");
   Serial.println(results->rawbuf[0] * USECPERTICK, DEC);
   for (int i = 1;  i < results->rawlen;  i++) {
-    int  x = results->rawbuf[i] * USECPERTICK;
+    unsigned int  x = results->rawbuf[i] * USECPERTICK;
     if (!(i & 1)) {  // even
       Serial.print("-");
       if (x < 1000)  Serial.print(" ") ;