drm/xe: Allow to trigger GT resets using debugfs writes

Today we allow to trigger GT resest by reading dedicated debugfs
files "force_reset" and "force_reset_sync" that we are exposing
using drm_info_list[] and drm_debugfs_create_files().

To avoid triggering potentially disruptive actions during otherwise
"safe" read operations, expose those two attributes using debugfs
function where we can specify file permissions and provide custom
"write" handler to trigger the GT resets also from there.

This step would allow us to drop triggering GT resets during read
operations, which we leave just to give users more time to switch.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://lore.kernel.org/r/20250519200914.216-1-michal.wajdeczko@intel.com