drm-ci: flaky tests for panfrost driver testing

[Vignesh Raman]

Hi Maintainers,

There are some flaky tests reported for panfrost driver testing in drm-ci.

# Board Name: rk3399-gru-kevin
# IGT Version: 1.28-g0df7b9b97
# Linux Version: 6.9.0-rc7
# Failure Rate: 50
panfrost_submit at pan-unhandled-pagefault

Will add these tests in 
drivers/gpu/drm/ci/xfails/rockchip-rk3399-flakes.txt 
(https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/Documentation/gpu/automated_testing.rst#n70)

Please could you have a look at these test results and let us know if 
you need more information. Thank you.

Regards,
Vignesh