Firmware image verification script is missing from repo

Quick helper script that checks using the built in functions of
OpenWRT that the firmware file uploaded is indeed a proper
firmware image.

fixes BBHN->Ticket:9

files/usr/local/bin/firmwarecheck.sh

@@ -0,0 +1,13 @@
+#!/bin/sh
+. /etc/functions.sh
+
+include /lib/upgrade/
+
+if (eval platform_check_image "$*")
+then
+	return 0;
+else
+	return 1;
+fi
+
+