gpu: host1x: Fix dma_free_wc() argument in the error path

If IOVA allocation or IOMMU mapping fails, dma_free_wc() is invoked with
size=0 because of a typo, that triggers "kernel BUG at mm/vmalloc.c:124!".
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/host1x/cdma.c

@@ -127,7 +127,7 @@ static int host1x_pushbuffer_init(struct push_buffer *pb)
 iommu_free_iova:
 	__free_iova(&host1x->iova, alloc);
 iommu_free_mem:
-	dma_free_wc(host1x->dev, pb->alloc_size, pb->mapped, pb->phys);
+	dma_free_wc(host1x->dev, size, pb->mapped, pb->phys);
 
 	return err;
 }