ar71xx: Buffalo WZR-HP-AG300H LED support

ar71xx: Buffalo WZR-HP-AG300H LED support

An improved LED support for Buffalo WZR-HP-AG300H.

There will be two new packages to go with this patch
(ar922x-led-fix-hotplug and ar922x-led-fix-init).
These packages essentially perform the same task of
disabling "JTAG over GPIO pins" function which is
currently required for LEDs on AR922x emac GPIO to work,
and are both considered a temporary fix that circumvent
this problem.

[juhosg: add the hotplug script from the proposed
ar922x-led-fix-hotplug package to ar71xx/base-files]

Signed-off-by: Yoichi Shinoda <shinoda@jaist.ac.jp>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@33294 3c298f89-4303-0410-b956-a3cf2f4a3e73