gpu: ion: Check return code of msm_allocate_iova_address

In the IOMMU heap, the return value of msm_allocate_iova_address
needs to be checked instead of the value of the iova address.
Check the return value instead.

Change-Id: I4554515d17c926a7dd738824aff21eb65d2ba56a
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
diff --git a/drivers/gpu/ion/ion_iommu_heap.c b/drivers/gpu/ion/ion_iommu_heap.c
index 621144b..9ea6f2b 100644
--- a/drivers/gpu/ion/ion_iommu_heap.c
+++ b/drivers/gpu/ion/ion_iommu_heap.c
@@ -196,7 +196,7 @@
 						data->mapped_size, align,
 						&data->iova_addr);
 
-	if (!data->iova_addr)
+	if (ret)
 		goto out;
 
 	domain = msm_get_iommu_domain(domain_num);