This symbols is not needed to get access to selecting the
GPIOLIB anymore: any arch can select GPIOLIB.

Cc: Michael Büsch <m@bues.ch>
Cc: Chris Zankel <chris@zankel.net>
Cc: linux-xtensa@linux-xtensa.org
Acked-by: NMax Filippov <jcmvbkbc@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>