drm/xe: Default auto_link_downgrade status to false

xe_pcode_read() can return back successfully without updating the
variable 'val'. This can cause an arbitrary value to show up in the
sysfs file.

Allow the auto_link_downgrade_status to default to 0 to avoid any
arbitrary value from coming up.

Fixes: 0e414bf7ad01 ("drm/xe: Expose PCIe link downgrade attributes")
Reviewed-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
Signed-off-by: Aradhya Bhatia <aradhya.bhatia@intel.com>
Link: https://lore.kernel.org/r/20250516124355.4872-1-aradhya.bhatia@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
(cherry picked from commit a7f87deac2295d11865048bcb9c2de369b52ed93)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>

Author: aradhyab7

drivers/gpu/drm/xe/xe_device_sysfs.c

@@ -124,7 +124,8 @@ auto_link_downgrade_status_show(struct device *dev, struct device_attribute *att
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct xe_device *xe = pdev_to_xe_device(pdev);
-	u32 val;
+	/* default the auto_link_downgrade status to 0 */
+	u32 val = 0;
 	int ret;
 
 	xe_pm_runtime_get(xe);