dmaengine: doc: client: Update for dmaengine_get_dma_device() usage

Client drivers should use the dmaengine_get_dma_device(chan) to get the
device pointer which should be used for DMA API for allocations and
mapping.

Signed-off-by: Peter Ujfalusi <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

Documentation/driver-api/dmaengine/client.rst

···
 
   .. code-block:: c
 
-     nr_sg = dma_map_sg(chan->device->dev, sgl, sg_len);
+     struct device *dma_dev = dmaengine_get_dma_device(chan);
+
+     nr_sg = dma_map_sg(dma_dev, sgl, sg_len);
 	if (nr_sg == 0)
 		/* error */