drm/xe: Initialize MOCS earlier

xe_mocs_init_early doesn't touch the hardware, it just sets up internal
software state.  There's no need to perform this step in the "forcewake
held" region.  Moving the init earlier will also make the uc_index
values available earlier which will be important for an upcoming GuC
init patch.

Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20230602235210.1314028-2-matthew.d.roper@intel.com


Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>