scsi: 3w-sas: 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-bit 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

Link: https://lore.kernel.org/r/dbbe8671ca[e-mail]
Signed-off-by: Christophe JAILLET <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/3w-sas.c

···
 	pci_try_set_mwi(pdev);
 
 	retval = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
-	if (retval)
-		retval = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
 	if (retval) {
 		TW_PRINTK(host, TW_DRIVER, 0x18, "Failed to set dma mask");
 		retval = -ENODEV;
···
 	pci_try_set_mwi(pdev);
 
 	retval = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
-	if (retval)
-		retval = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
 	if (retval) {
 		TW_PRINTK(host, TW_DRIVER, 0x25, "Failed to set dma mask during resume");
 		retval = -ENODEV;