drm/omap: Use writecombine for descriptors

Use writecombine for descriptor and PAT programming memory.
Signed-off-by: Andy Gross <andy.gross@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/omapdrm/omap_dmm_tiler.c

@@ -525,7 +525,7 @@ static int omap_dmm_remove(struct platform_device *dev)
 
 		kfree(omap_dmm->engines);
 		if (omap_dmm->refill_va)
-			dma_free_coherent(omap_dmm->dev,
+			dma_free_writecombine(omap_dmm->dev,
 				REFILL_BUFFER_SIZE * omap_dmm->num_engines,
 				omap_dmm->refill_va,
 				omap_dmm->refill_pa);
@@ -633,7 +633,7 @@ static int omap_dmm_probe(struct platform_device *dev)
 	omap_dmm->dummy_pa = page_to_phys(omap_dmm->dummy_page);
 
 	/* alloc refill memory */
-	omap_dmm->refill_va = dma_alloc_coherent(&dev->dev,
+	omap_dmm->refill_va = dma_alloc_writecombine(&dev->dev,
 				REFILL_BUFFER_SIZE * omap_dmm->num_engines,
 				&omap_dmm->refill_pa, GFP_KERNEL);
 	if (!omap_dmm->refill_va) {