MIPS: Move Loongson GPIO driver to drivers/gpio

Move Loongson-2's GPIO driver to drivers/gpio and add Kconfig options.

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/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 9b2d350..473511f 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -508,6 +508,12 @@
 	  Select this to support Aeroflex Gaisler GRGPIO cores from the GRLIB
 	  VHDL IP core library.
 
+config GPIO_LOONGSON
+	bool "Loongson-2 GPIO support"
+	depends on CPU_LOONGSON2
+	help
+	  driver for GPIO functionality on Loongson-2F processors.
+
 config GPIO_TB10X
 	bool
 	select GENERIC_IRQ_CHIP