ci: Limit Intel CPU scaling frequency for performance tests
As an additional measure to mitigate thermal throttling, set the upper limit for the CPU scaling frequency to 65% of maximum allowed by the hardware.
Please note the impact on the overall tests duration should be minimal since the performance tests do not rely much on the CPU, they mostly stress the GPU.
Signed-off-by: Cristian Ciocaltea cristian.ciocaltea@collabora.com