drm/tegra: vic: Handle tegra_drm_alloc() failure

This function can return one of several errors in an ERR_PTR()-encoded
pointer, so make sure to propogate those on failure.
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/vic.c

@@ -237,6 +237,8 @@ static int vic_load_firmware(struct vic *vic)
 			return -ENOMEM;
 	} else {
 		virt = tegra_drm_alloc(tegra, size, &iova);
+		if (IS_ERR(virt))
+			return PTR_ERR(virt);
 	}
 
 	vic->falcon.firmware.virt = virt;