gpio: mcp230xx: Introduce new driver

Introduce driver for I2C based MCP230xx GPIO chips, which are
quite common and already well supported by the Linux kernel.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 16b09fb..58f4704 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -24,6 +24,7 @@
 obj-$(CONFIG_KONA_GPIO)	+= kona_gpio.o
 obj-$(CONFIG_MARVELL_GPIO)	+= mvgpio.o
 obj-$(CONFIG_MARVELL_MFP)	+= mvmfp.o
+obj-$(CONFIG_MCP230XX_GPIO)	+= mcp230xx_gpio.o
 obj-$(CONFIG_MXC_GPIO)	+= mxc_gpio.o
 obj-$(CONFIG_MXS_GPIO)	+= mxs_gpio.o
 obj-$(CONFIG_PCA953X)		+= pca953x.o