IB/hfi1: Ignore link downgrade with 0 lanes

Versions of the 8051 firmware < 0.38 may report a link failure
as a link downgrade with a width of 0 followed by a link down
notification.  Ignore the zero width downgrade notification -
the driver should follow the link down path.

Reviewed-by: Easwar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/staging/rdma/hfi1/chip.c

@@ -7336,7 +7336,11 @@ retry:
 		ppd->link_width_downgrade_rx_active = rx;
 	}
 
-	if (lwde == 0) {
+	if (ppd->link_width_downgrade_tx_active == 0 ||
+	    ppd->link_width_downgrade_rx_active == 0) {
+		/* the 8051 reported a dead link as a downgrade */
+		dd_dev_err(ppd->dd, "Link downgrade is really a link down, ignoring\n");
+	} else if (lwde == 0) {
 		/* downgrade is disabled */
 
 		/* bounce if not at starting active width */