ata: ahci_xgene: potential NULL dereference in probe

Smatch complains about this potential NULL dereference of "acpi_id".

Fixes: c9802a4b ('ata: ahci_xgene: Add AHCI Support for 2nd HW version of APM X-Gene SoC AHCI SATA Host controller.')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

drivers/ata/ahci_xgene.c

@@ -732,9 +732,7 @@ static int xgene_ahci_probe(struct platform_device *pdev)
 		if (!acpi_id) {
 			dev_warn(&pdev->dev, "No node entry in ACPI table. Assume version1\n");
 			version = XGENE_AHCI_V1;
-		}
-
-		if (acpi_id->driver_data) {
+		} else if (acpi_id->driver_data) {
 			version = (enum xgene_ahci_version) acpi_id->driver_data;
 			status = acpi_get_object_info(ACPI_HANDLE(&pdev->dev), &info);
 			if (ACPI_FAILURE(status)) {