As per example from the other ARM boards, push the DaVinci TNET
GPIO driver down to the GPIO subsystem so it can be consolidated.

Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>