dma-direct: mark as is_phys

Various PCI_DMA_BUS_IS_PHYS implementations rely on this flag to make proper
decisions for block and networking addressability.
Signed-off-by: NChristoph Hellwig <hch@lst.de>

lib/dma-direct.c

@@ -152,5 +152,6 @@ const struct dma_map_ops dma_direct_ops = {
 	.map_sg			= dma_direct_map_sg,
 	.dma_supported		= dma_direct_supported,
 	.mapping_error		= dma_direct_mapping_error,
+	.is_phys		= 1,
 };
 EXPORT_SYMBOL(dma_direct_ops);