drm/msm: no mmu is only error if not using vram carveout

Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/msm_gem.c

@@ -278,24 +278,23 @@ int msm_gem_get_iova_locked(struct drm_gem_object *obj, int id,
 		uint32_t *iova)
 {
 	struct msm_gem_object *msm_obj = to_msm_bo(obj);
-	struct drm_device *dev = obj->dev;
 	int ret = 0;
 
 	if (!msm_obj->domain[id].iova) {
 		struct msm_drm_private *priv = obj->dev->dev_private;
-		struct msm_mmu *mmu = priv->mmus[id];
 		struct page **pages = get_pages(obj);
 
-		if (!mmu) {
-			dev_err(dev->dev, "null MMU pointer\n");
-			return -EINVAL;
-		}
-
 		if (IS_ERR(pages))
 			return PTR_ERR(pages);
 
 		if (iommu_present(&platform_bus_type)) {
-			uint32_t offset = (uint32_t)mmap_offset(obj);
+			struct msm_mmu *mmu = priv->mmus[id];
+			uint32_t offset;
+
+			if (WARN_ON(!mmu))
+				return -EINVAL;
+
+			offset = (uint32_t)mmap_offset(obj);
 			ret = mmu->funcs->map(mmu, offset, msm_obj->sgt,
 					obj->size, IOMMU_READ | IOMMU_WRITE);
 			msm_obj->domain[id].iova = offset;