gpio: stp-xway: allow compile-testing

Enable compile-testing of the stp-xway GPIO driver now that it does not
depend on any architecture specific includes anymore.
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20190702223248.31934-5-martin.blumenstingl@googlemail.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -489,7 +489,8 @@ config GPIO_STA2X11
 
 config GPIO_STP_XWAY
 	bool "XWAY STP GPIOs"
-	depends on SOC_XWAY
+	depends on SOC_XWAY || COMPILE_TEST
+	depends on OF_GPIO
 	help
 	  This enables support for the Serial To Parallel (STP) unit found on
 	  XWAY SoC. The STP allows the SoC to drive a shift registers cascade,