Disable STDIN input to allow deepsleep

Author: facchinm

cores/arduino/main.cpp

@@ -33,6 +33,8 @@ void setupUSB() { }
 
 int main(void)
 {
+	// we are never going to use getchar/scanf directly
+	mbed::mbed_file_handle(STDIN_FILENO)->enable_input(false);
 	init();
 	initVariant();