ci/broadcom: retry always when serial log timeout

So far we were retrying the testing (through device rebooting) if we did
not detect the boot sequence.

But found a couple of times that the serial log can also be "lost"
during the testing process. In all those times a manual retry of the job
was enough to complete the test.

Thus, let's apply the retry once automatically in this case.

Signed-off-by: Juan A. Suarez Romero <jasuarez@igalia.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9335>

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

@@ -75,7 +75,7 @@ class PoERun:
                     return 1
 
         self.print_error("Reached the end of the CPU serial log without finding a result")
-        return 1
+        return 2
 
 def main():
     parser = argparse.ArgumentParser()