busvoodoo: set LED when HiZ is started

lib/busvoodoo_hiz.c

@@ -49,6 +49,7 @@ static bool busvoodoo_hiz_setup(char** prefix, const char* line)
 {
 	(void)line; // no configuration is required
 	*prefix = "HiZ"; // set command line prefix
+	led_blink(0, 1); // switch blue LED on to show we are ready
 	return true;	
 }