gpio: Loongson1: add Loongson1 GPIO driver

This patch adds GPIO driver for Loongson1B.

Signed-off-by: Kelvin Cheung <keguang.zhang@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 1e0b74f..40ab913 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -127,3 +127,4 @@
 obj-$(CONFIG_GPIO_ZEVIO)	+= gpio-zevio.o
 obj-$(CONFIG_GPIO_ZYNQ)		+= gpio-zynq.o
 obj-$(CONFIG_GPIO_ZX)		+= gpio-zx.o
+obj-$(CONFIG_GPIO_LOONGSON1)	+= gpio-loongson1.o