gpio: remove obsolete tnetv107x driver

The tnetv107x platform is getting removed, so this driver won't
be needed any more.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: linux-gpio@vger.kernel.org
Acked-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>