We need to enable MC CAC for mclk switching to work.

Fixes: d765129a ("drm/amd/pm: correct sclk/mclk dpm enablement")
Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1561Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org