drm/xe/guc_pc: Fix Meteor Lake registers.

When adding the frequency management, Meteor Lake platform
was left behind. Handling it properly now.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Cc: Francois Dugast <francois.dugast@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>