examples/hdc1008_demo: fix formatting after decimal point

Modulo operation used to calculate digits after decimal point,
but if that result is <10, a leading zero wasn't added, giving a
wrong value.

Same as 34c7bec0dc
but on the example app.

examples/hdc1008_demo/hdc1008_main.c

@@ -99,7 +99,7 @@ int main(int argc, FAR char *argv[])
 
   printf("Temperature and humidity (ioctl)\n"
          "================================\n");
-  printf("t=%d.%d, h=%d.%d\n\n",
+  printf("t=%d.%02d, h=%d.%d\n\n",
           data.temperature / 100, data.temperature % 100,
           data.humidity / 10, data.humidity % 10);