ARM: delete old reference to ARM_GPIOLIB_COMPLEX

This inclusion guard became pointless after commit
40ca061b


"ARM: 7841/1: sa1100: remove complex GPIO interface"
which removed the last complex gpiolib interface.

Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>