udmabuf: use sgtable-based scatterlist wrappers

Use common wrappers operating directly on the struct sg_table objects to
fix incorrect use of scatterlists sync calls. dma_sync_sg_for_*()
functions have to be called with the number of elements originally passed
to dma_map_sg_*() function, not the one returned in sgtable's nents.

Fixes: 1ffe09590121 ("udmabuf: fix dma-buf cpu access")
CC: [e-mail]
Signed-off-by: Marek Szyprowski <[e-mail]>
Acked-by: Vivek Kasireddy <[e-mail]>
Reviewed-by: Christian König <[e-mail]>
Signed-off-by: Christian König <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/dma-buf/udmabuf.c

···
 			ubuf->sg = NULL;
 		}
 	} else {
-		dma_sync_sg_for_cpu(dev, ubuf->sg->sgl, ubuf->sg->nents,
-				    direction);
+		dma_sync_sgtable_for_cpu(dev, ubuf->sg, direction);
 	}
 
 	return ret;
···
 	if (!ubuf->sg)
 		return -EINVAL;
 
-	dma_sync_sg_for_device(dev, ubuf->sg->sgl, ubuf->sg->nents, direction);
+	dma_sync_sgtable_for_device(dev, ubuf->sg, direction);
 	return 0;
 }