soc: Allow test-building of MediaTek drivers

The COMPILE_TEST alternative dependency allows test-building the
drivers but only as long as the build system itself will look into
the directory where the drivers reside.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Sean Wang <sean.wang@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Acked-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

drivers/soc/Makefile

@@ -10,7 +10,7 @@ obj-$(CONFIG_MACH_DOVE)		+= dove/
 obj-y				+= fsl/
 obj-$(CONFIG_ARCH_MXC)		+= imx/
 obj-$(CONFIG_SOC_XWAY)		+= lantiq/
-obj-$(CONFIG_ARCH_MEDIATEK)	+= mediatek/
+obj-y				+= mediatek/
 obj-$(CONFIG_ARCH_MESON)	+= amlogic/
 obj-$(CONFIG_ARCH_QCOM)		+= qcom/
 obj-y				+= renesas/