drm/xe/gt: Use scope-based cleanup

drm/xe/gt: Use scope-based cleanup

Using scope-based cleanup for forcewake and runtime PM allows us to
reduce or eliminate some of the goto-based error handling and simplify
several functions.

v2:
 - Drop changes to do_gt_restart().  This function still has goto-based
   logic, making scope-based cleanup unsafe for now.  (Gustavo)

Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Link: https://patch.msgid.link/20251118164338.3572146-32-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>