pinctrl: mcp23s08: Kconfig: update to reflect supported features

Commit d8f4494e removed comments which described this limitation.
The code supported interrupts even before.

Also add some spacing so that the chip IDs are a bit more readable.
Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Reviewed-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/Kconfig

@@ -161,10 +161,10 @@ config PINCTRL_MCP23S08
 	select REGMAP_SPI if SPI_MASTER
 	select GENERIC_PINCONF
 	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.
+	  SPI/I2C driver for Microchip MCP23S08 / MCP23S17 / MCP23S18 /
+	  MCP23008 / MCP23017 / MCP23018 I/O expanders.
+	  This provides a GPIO interface supporting inputs and outputs and a
+	  corresponding interrupt-controller.
 
 config PINCTRL_OXNAS
 	bool