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>

arch/mips/Kconfig

@@ -1395,7 +1395,6 @@ config CPU_LOONGSON1B
 	bool "Loongson 1B"
 	depends on SYS_HAS_CPU_LOONGSON1B
 	select CPU_LOONGSON1
-	select ARCH_WANT_OPTIONAL_GPIOLIB
 	select LEDS_GPIO_REGISTER
 	help
 	  The Loongson 1B is a 32-bit SoC, which implements the MIPS32