ARM: dma-mapping: Set arm_dma_set_mask() for iommu->set_dma_mask()

struct dma_map_ops iommu_ops doesn't have ->set_dma_mask, which causes
crash when dma_set_mask() is called from some driver.

Signed-off-by: Hiroshi Doyu <[e-mail]>
Signed-off-by: Marek Szyprowski <[e-mail]>

arch/arm/mm/dma-mapping.c

···
 	.unmap_sg		= arm_iommu_unmap_sg,
 	.sync_sg_for_cpu	= arm_iommu_sync_sg_for_cpu,
 	.sync_sg_for_device	= arm_iommu_sync_sg_for_device,
+
+	.set_dma_mask		= arm_dma_set_mask,
 };
 
 struct dma_map_ops iommu_coherent_ops = {
···
 
 	.map_sg		= arm_coherent_iommu_map_sg,
 	.unmap_sg	= arm_coherent_iommu_unmap_sg,
+
+	.set_dma_mask	= arm_dma_set_mask,
 };
 
 /**