pistachio: use generic diag.sh

Remove local diag.sh in favor of generic one and add the required
led-* aliases to DTS.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

target/linux/pistachio/base-files/etc/diag.sh

@@ -1,30 +0,0 @@
-#!/bin/sh
-#
-# Copyright (C) 2017 OpenWrt.org
-#
-# This is free software, licensed under the GNU General Public License v2.
-# See /LICENSE for more information.
-#
-
-. /lib/functions/leds.sh
-
-status_led="marduk:red:heartbeat"
-
-set_state() {
-
-	case "$1" in
-	preinit)
-		status_led_blink_preinit
-		;;
-	failsafe)
-		status_led_blink_failsafe
-		;;
-	upgrade | \
-	preinit_regular)
-		status_led_blink_preinit_regular
-		;;
-	done)
-		status_led_on
-		;;
-	esac
-}