ci/bare-metal: Restart a run on intermittent kernel lockups.

Since enabling SMP on db820c and cranking up how many tests we run, we've
been seeing lockups like this a couple of times a week.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9655>

.gitlab-ci/bare-metal/cros_servo_run.py

@@ -139,6 +139,12 @@ class CrosServoRun:
                 self.print_error("Detected cheza power management bus error, restarting run...")
                 return 2
 
+            # db820c sometimes wedges around iommu fault recovery
+            if re.search("watchdog: BUG: soft lockup - CPU.* stuck", line):
+                self.print_error(
+                    "Detected kernel soft lockup, restarting run...")
+                return 2
+
             result = re.search("bare-metal result: (\S*)", line)
             if result:
                 if result.group(1) == "pass":