radv/ci: set a tight timeout on vkcts-navi31

These jobs need to run in pre-merge, so let's make sure their execution
time remains in check so as not to block merges due to non-merge
pipelines.

Signed-off-by: Martin Roukala (né Peres) <martin.roukala@mupuf.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33486>
1 file changed