DT file doesn't include any GPIOs yet, but let's add it as we got some
interest in this device on IRC.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@42864 3c298f89-4303-0410-b956-a3cf2f4a3e73