dmaengine: mv_xor: Use correct device for DMA API

Using dma_dev->dev for mappings before it's assigned with the correct
device is unlikely to work as expected, and with future dma-direct
changes, passing a NULL device may end up crashing entirely. I don't
know enough about this hardware or the mv_xor_prep_dma_interrupt()
operation to implement the appropriate error-handling logic that would
have revealed those dma_map_single() calls failing on arm64 for as long
as the driver has been enabled there, but moving the assignment earlier
will at least make the current code operate as intended.

Fixes: 22843545 ("dma: mv_xor: Add support for DMA_INTERRUPT")
Reported-by: John David Anglin <dave.anglin@bell.net>
Tested-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Tested-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/mv_xor.c

@@ -1059,6 +1059,7 @@ mv_xor_channel_add(struct mv_xor_device *xordev,
 		mv_chan->op_in_desc = XOR_MODE_IN_DESC;
 
 	dma_dev = &mv_chan->dmadev;
+	dma_dev->dev = &pdev->dev;
 	mv_chan->xordev = xordev;
 
 	/*
@@ -1091,7 +1092,6 @@ mv_xor_channel_add(struct mv_xor_device *xordev,
 	dma_dev->device_free_chan_resources = mv_xor_free_chan_resources;
 	dma_dev->device_tx_status = mv_xor_status;
 	dma_dev->device_issue_pending = mv_xor_issue_pending;
-	dma_dev->dev = &pdev->dev;
 
 	/* set prep routines based on capability */
 	if (dma_has_cap(DMA_INTERRUPT, dma_dev->cap_mask))