board-tuna-connector.c: fix a bug on the dock mode of this device. Originally reported by cynewulf - more information here: http://rootzwiki.com/topic/29281-howto-reenable-hdmi-mirroring-on-gnexus-portrait-dock-for-android-403-and-up/

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>