ci/bare-metal: Move the "POWER_GOOD not seen in time" check to the right time.

The poweron failure happens before we get to the bootloader
("load_archive: loading locale_en.bin") not after we're trying to boot the
kernel and we're waiting for the deqp run to complete.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6970>

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

@@ -87,11 +87,6 @@ class CrosServoRun:
                 self.cpu_write("\016")
                 break
 
-        tftp_failures = 0
-        for line in self.serial_queue_lines():
-            if re.search("---. end Kernel panic", line):
-                return 1
-
             # The Cheza boards have issues with failing to bring up power to
             # the system sometimes, possibly dependent on ambient temperature
             # in the farm.
@@ -99,6 +94,11 @@ class CrosServoRun:
                 print("Detected intermittent poweron failure, restarting run...")
                 return 2
 
+        tftp_failures = 0
+        for line in self.serial_queue_lines():
+            if re.search("---. end Kernel panic", line):
+                return 1
+
             # The Cheza firmware seems to occasionally get stuck looping in
             # this error state during TFTP booting, possibly based on amount of
             # network traffic around it, but it'll usually recover after a