gpiolib: add build option for CDEV v1 ABI

Add a build option to allow the removal of the CDEV v1 ABI.
Suggested-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: NKent Gibson <warthog618@gmail.com>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>

drivers/gpio/Kconfig

@@ -82,6 +82,18 @@ config GPIO_CDEV
 
 	  If unsure, say Y.
 
+config GPIO_CDEV_V1
+	bool "Support GPIO ABI Version 1"
+	default y
+	depends on GPIO_CDEV
+	help
+	  Say Y here to support version 1 of the GPIO CDEV ABI.
+
+	  This ABI version is deprecated.
+	  Please use the latest ABI for new developments.
+
+	  If unsure, say Y.
+
 config GPIO_GENERIC
 	depends on HAS_IOMEM # Only for IOMEM drivers
 	tristate