drm/ci: force-enable CONFIG_MSM_MMCC_8996 as built-in

Enable CONFIG_MSM_MMCC_8996, the multimedia clock controller on Qualcomm
MSM8996 to prevent the the board from hitting the probe deferral
timeouts in CI run.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: Helen Koike <helen.koike@collabora.com>
Acked-by: Helen Koike <helen.koike@collabora.com>
Link: https://lore.kernel.org/r/20231008132320.762542-2-dmitry.baryshkov@linaro.org


Signed-off-by: Maxime Ripard <mripard@kernel.org>