ci: reduce bare-metal retries of poe_run to only 3 attempts

10 is overkill, if we fail that many times in a row we should stop
trying on this runner.

Signed-off-by: Eric Engestrom <eric@igalia.com>
Reviewed-by: David Heidelberg <david.heidelberg@collabora.com>
Reviewed-by: Juan A. Suarez <jasuarez@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24407>

.gitlab-ci/bare-metal/poe-powered.sh

@@ -159,7 +159,7 @@ echo "$BM_CMDLINE" > /tftp/cmdline.txt
 printf "$BM_BOOTCONFIG" >> /tftp/config.txt
 
 set +e
-ATTEMPTS=10
+ATTEMPTS=3
 while [ $((ATTEMPTS--)) -gt 0 ]; do
   python3 $BM/poe_run.py \
           --dev="$BM_SERIAL" \