drm/xe: Apply Wa_14020316580 in xe_gt_idle_enable_pg()

drm/xe: Apply Wa_14020316580 in xe_gt_idle_enable_pg()

Wa_14020316580 was getting clobbered by power gating init code
later in the driver load sequence. Move the Wa so that
it applies correctly.

Fixes: 7cd05ef89c9d ("drm/xe/xe2hpm: Add initial set of workarounds")
Suggested-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Reviewed-by: Riana Tauro <riana.tauro@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patch.msgid.link/20251129052548.70766-1-vinay.belgaumkar@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>