dmaengine: idxd: Remove useless DMA-32 fallback configuration

As stated in [1], dma_set_mask() with a 64-bit mask never fails if
dev->dma_mask is non-NULL.
So, if it fails, the 32 bits case will also fail for the same reason.

Simplify code and remove some dead code accordingly.

[1]: https://lore.kernel.org/linux-kernel/[e-mail]/#t

Signed-off-by: Christophe JAILLET <[e-mail]>
Acked-by: Dave Jiang <[e-mail]>
Link: https://lore.kernel.org/r/009c80294d[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/idxd/init.c

···
 	dev_dbg(dev, "Set DMA masks\n");
 	rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
 	if (rc)
-		rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
-	if (rc)
 		goto err;
 
 	dev_dbg(dev, "Set PCI master\n");