sniffer: set LED pattern

The red and green LEDs are now used as follows:
- red on = power (firmware is running)
- red blink = error detected (e.g. during ISO-7816 parsing)
- green on = running (sniffer mode is running)
- green blink = activity (e.g. USB message sent)

Change-Id: Ib1b6ff87fb92d6ed3ecae4bc89386206aaab508e

firmware/libcommon/source/sniffer.c

@@ -302,7 +302,7 @@ static void usb_send_data(enum simtrace_msg_type_sniff type, const uint8_t* data
 	}
 
 	/* Show activity on LED */
-	led_blink(LED_GREEN, BLINK_2O_F);
+	led_blink(LED_GREEN, BLINK_2F_O);
 
 	/* Print message */
 	switch (type) {