drm/mediatek: Allow build with COMPILE_TEST=y

Allow mediatek to be built with COMPILE_TEST=y for greater
coverage. Builds fine on x86/x86_64 at least.

Cc: Chun-Kuang Hu <[e-mail]>
Cc: Philipp Zabel <[e-mail]>
Cc: [e-mail]
Signed-off-by: Ville Syrjälä <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Reviewed-by: CK Hu <[e-mail]>

drivers/gpu/drm/mediatek/Kconfig

···
 config DRM_MEDIATEK
 	tristate "DRM Support for Mediatek SoCs"
 	depends on DRM
-	depends on ARCH_MEDIATEK || (ARM && COMPILE_TEST)
+	depends on (ARCH_MEDIATEK && ARM) || COMPILE_TEST
 	depends on COMMON_CLK
-	depends on HAVE_ARM_SMCCC
+	depends on HAVE_ARM_SMCCC || COMPILE_TEST
 	depends on OF
 	depends on MTK_MMSYS
 	select DRM_CLIENT_SELECTION