dma-direct: use phys_to_dma_direct in dma_direct_alloc

Replace the currently open code copy.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>

kernel/dma/direct.c

@@ -240,10 +240,7 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 			goto out_encrypt_pages;
 	}
 done:
-	if (force_dma_unencrypted(dev))
-		*dma_handle = __phys_to_dma(dev, page_to_phys(page));
-	else
-		*dma_handle = phys_to_dma(dev, page_to_phys(page));
+	*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
 	return ret;
 
 out_encrypt_pages: