pinctrl: mediatek: Add Pinctrl/GPIO driver for mt8135.

The mediatek SoCs have GPIO controller that handle both the muxing and GPIOs.

The GPIO controller have pinmux, pull enable, pull select, direction and output high/low control.

This driver include common driver and mt8135 part.
The common driver include the pinctrl driver and GPIO driver.
The mt8135 part contain its special device data.

Signed-off-by: Hongzhou Yang <hongzhou.yang@mediatek.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/pinctrl/Makefile b/drivers/pinctrl/Makefile
index 3d62946..e54d216 100644
--- a/drivers/pinctrl/Makefile
+++ b/drivers/pinctrl/Makefile
@@ -49,3 +49,4 @@
 obj-$(CONFIG_PLAT_SPEAR)	+= spear/
 obj-$(CONFIG_ARCH_SUNXI)	+= sunxi/
 obj-$(CONFIG_ARCH_VT8500)	+= vt8500/
+obj-$(CONFIG_ARCH_MEDIATEK)	+= mediatek/