Disable print fan monitoring

Print fan's third pin is no longer connected for monitoring RPM.

Firmware/temperature.cpp

@@ -572,10 +572,12 @@ void checkFanSpeed()
     host_keepalive();
   }
 #endif
+/*
 #if (defined(FANCHECK) && defined(TACH_1) && (TACH_1 >-1))
 	if ((fan_speed[1] < 5) && ((blocks_queued() ? block_buffer[block_buffer_tail].fan_speed : fanSpeed) > MIN_PRINT_FAN_SPEED)) fan_speed_errors[1]++;
 	else fan_speed_errors[1] = 0;
 #endif
+*/
 
 	// drop the fan_check_error flag when both fans are ok
 	if( fan_speed_errors[0] == 0 && fan_speed_errors[1] == 0 && fan_check_error == EFCE_REPORTED){