MIPS: Delete use of ARCH_WANT_OPTIONAL_GPIOLIB

The Loongson1 added a new instance of ARCH_WANT_OPTIONAL_GPIOLIB
which is no longer required to have GPIOLIB available in
Kconfig. Delete it.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13543/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>