pinctrl: change Kconfig PINCTRL variable to a menuconfig

This allows PINCTRL to be selected manually to allow enabling of the
mcp23s08 i2c/spi gpio driver. Which is not platform specific.
Signed-off-by: NPhil Reid <preid@electromag.com.au>
Reviewed-by: NSebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/Kconfig

@@ -2,11 +2,10 @@
 # PINCTRL infrastructure and drivers
 #
 
-config PINCTRL
-	bool
+menuconfig PINCTRL
+	bool "Pin controllers"
 
-menu "Pin controllers"
-	depends on PINCTRL
+if PINCTRL
 
 config GENERIC_PINCTRL_GROUPS
 	bool
@@ -379,4 +378,4 @@ config PINCTRL_TB10X
 	depends on OF && ARC_PLAT_TB10X
 	select GPIOLIB
 
-endmenu
+endif