gpio: moxart: Allow compile test build

There is no build dependency for this driver, so enable COMPILE_TEST to get
better build coverage.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 619767b..96ad29d 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -280,7 +280,7 @@
 
 config GPIO_MOXART
 	bool "MOXART GPIO support"
-	depends on ARCH_MOXART
+	depends on ARCH_MOXART || COMPILE_TEST
 	select GPIO_GENERIC
 	help
 	  Select this option to enable GPIO driver for