ci: Provide intel-gpu-freq.sh in LAVA and bare-metal rootfs

ci: Provide intel-gpu-freq.sh in LAVA and bare-metal rootfs

The script will be used for tuning Intel GPU frequency to maximize
performance tests execution, while also trying to reduce throttling,
which has a negative impact on results consistency.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Acked-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Guilherme Gallo <guilherme.gallo@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15662>