drm/imx: allow building under COMPILE_TEST

Allow to compile-test imx-drm on other platforms.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpu/drm/imx/Kconfig b/drivers/gpu/drm/imx/Kconfig
index c554284..c3c84a0 100644
--- a/drivers/gpu/drm/imx/Kconfig
+++ b/drivers/gpu/drm/imx/Kconfig
@@ -4,7 +4,7 @@
 	select VIDEOMODE_HELPERS
 	select DRM_GEM_CMA_HELPER
 	select DRM_KMS_CMA_HELPER
-	depends on DRM && (ARCH_MXC || ARCH_MULTIPLATFORM)
+	depends on DRM && (ARCH_MXC || ARCH_MULTIPLATFORM || COMPILE_TEST)
 	depends on IMX_IPUV3_CORE
 	help
 	  enable i.MX graphics support