media: venus: fix compile-test build on non-qcom ARM platform

If QCOM_MDT_LOADER is enabled, but ARCH_QCOM is not, we run into
a build error:

ERROR: "qcom_mdt_load" [drivers/media/platform/qcom/venus/venus-core.ko] undefined!
ERROR: "qcom_mdt_get_size" [drivers/media/platform/qcom/venus/venus-core.ko] undefined!

This changes the 'select' statement again, so we only try to enable
those symbols when the drivers will actually get built, and explicitly
test for QCOM_MDT_LOADER to be enabled before calling into it.

Fixes: 76724b30 ("[media] media: venus: enable building with COMPILE_TEST")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/Kconfig

@@ -475,8 +475,8 @@ config VIDEO_QCOM_VENUS
 	tristate "Qualcomm Venus V4L2 encoder/decoder driver"
 	depends on VIDEO_DEV && VIDEO_V4L2 && HAS_DMA
 	depends on (ARCH_QCOM && IOMMU_DMA) || COMPILE_TEST
-	select QCOM_MDT_LOADER if (ARM || ARM64)
-	select QCOM_SCM if (ARM || ARM64)
+	select QCOM_MDT_LOADER if ARCH_QCOM
+	select QCOM_SCM if ARCH_QCOM
 	select VIDEOBUF2_DMA_SG
 	select V4L2_MEM2MEM_DEV
 	---help---

drivers/media/platform/qcom/venus/firmware.c

@@ -40,7 +40,7 @@ int venus_boot(struct device *parent, struct device *fw_dev, const char *fwname)
 	void *mem_va;
 	int ret;
 
-	if (!qcom_scm_is_available())
+	if (!IS_ENABLED(CONFIG_QCOM_MDT_LOADER) || !qcom_scm_is_available())
 		return -EPROBE_DEFER;
 
 	fw_dev->parent = parent;