RMT: Fix in bitshift of NeoPixel example project

Fixed bit shift in demo application of using RMT peripheral. Init data array to be transmitted was off by one, as for the first iteration (i==0) the mask was 1<<8, which results in shifted RGB value in color variable
Closes espressif#2921

Author: david-cermak

libraries/ESP32/examples/RMT/RMTWriteNeoPixel/RMTWriteNeoPixel.ino

@@ -62,7 +62,7 @@ void loop()
     for (led=0; led<NR_OF_LEDS; led++) {
         for (col=0; col<3; col++ ) {
             for (bit=0; bit<8; bit++){
-                if ( (color[col] & (1<<(8-bit))) && (led == led_index) ) {
+                if ( (color[col] & (1<<(7-bit))) && (led == led_index) ) {
                     led_data[i].level0 = 1;
                     led_data[i].duration0 = 8;
                     led_data[i].level1 = 0;