gpio: mcp23s08: move to pinctrl

This moves the mcp23s08 driver from gpio to pinctrl. Actual
pinctrl support for configuration of the pull-up resistors
follows in its own patch.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Acked-by: Sylvain Lemieux <slemieux.tyco@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -1227,23 +1227,6 @@ config GPIO_PISOSR
 
 endmenu
 
-menu "SPI or I2C GPIO expanders"
-	depends on (SPI_MASTER && !I2C) || I2C
-
-config GPIO_MCP23S08
-	tristate "Microchip MCP23xxx I/O expander"
-	depends on OF_GPIO
-	select GPIOLIB_IRQCHIP
-	select REGMAP_I2C if I2C
-	select REGMAP if SPI_MASTER
-	help
-	  SPI/I2C driver for Microchip MCP23S08/MCP23S17/MCP23008/MCP23017
-	  I/O expanders.
-	  This provides a GPIO interface supporting inputs and outputs.
-	  The I2C versions of the chips can be used as interrupt-controller.
-
-endmenu
-
 menu "USB GPIO expanders"
 	depends on USB