scsi: hisi_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/YL3vSPK5DXTNvgdx@infradead.org/#t

Link: https://lore.kernel.org/r/1bf2d3660178b0e6f172e5208bc0bd68d31d9268.1642237482.git.christophe.jaillet@wanadoo.frAcked-by: John Garry <john.garry@huawei.com>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/hisi_sas/hisi_sas_main.c

@@ -2666,9 +2666,6 @@ static struct Scsi_Host *hisi_sas_shost_alloc(struct platform_device *pdev,
 		goto err_out;
 
 	error = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
-	if (error)
-		error = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
-
 	if (error) {
 		dev_err(dev, "No usable DMA addressing method\n");
 		goto err_out;

drivers/scsi/hisi_sas/hisi_sas_v3_hw.c

@@ -4695,8 +4695,6 @@ hisi_sas_v3_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		goto err_out;
 
 	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) {
 		dev_err(dev, "No usable DMA addressing method\n");
 		rc = -ENODEV;