gpio: loongson: Add Loongson-3A/3B GPIO driver support

Improve Loongson-2's GPIO driver to support Loongson-3A/3B, and update
Loongson-3's default config file.

Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index c7a1690..1ecd499 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1245,6 +1245,7 @@
 	select CPU_SUPPORTS_HUGEPAGES
 	select WEAK_ORDERING
 	select WEAK_REORDERING_BEYOND_LLSC
+	select ARCH_REQUIRE_GPIOLIB
 	help
 		The Loongson 3 processor implements the MIPS64R2 instruction
 		set with many extensions.