ci/broadcom: retry always when serial log timeout

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>