gpio: xgene-sb: Allow driver to be built with COMPILE_TEST

Allow driver to be built with COMPILE_TEST for better test coverage.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200512182721.55127-2-andriy.shevchenko@linux.intel.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -638,7 +638,7 @@ config GPIO_XGENE
 
 config GPIO_XGENE_SB
 	tristate "APM X-Gene GPIO standby controller support"
-	depends on ARCH_XGENE
+	depends on (ARCH_XGENE || COMPILE_TEST)
 	select GPIO_GENERIC
 	select GPIOLIB_IRQCHIP
 	select IRQ_DOMAIN_HIERARCHY