gpio: zx: depend on ARCH_ZX

Set GPIO_ZX to depend on ARCH_ZX as it's SOC specific.
Signed-off-by: NPeter Robinson <pbrobinson@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -524,6 +524,7 @@ config GPIO_ZYNQ
 
 config GPIO_ZX
 	bool "ZTE ZX GPIO support"
+	depends on ARCH_ZX || COMPILE_TEST
 	select GPIOLIB_IRQCHIP
 	help
 	  Say yes here to support the GPIO device on ZTE ZX SoCs.