drm/xe: Store pointer to struct xe_gt in gt/ debugfs directory

Attributes added under 'gt/' directories may wish to use that
in case they can't obtain it from elsewhere.
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20240214115756.1525-2-michal.wajdeczko@intel.comSigned-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240328162808.451-2-michal.wajdeczko@intel.com

drivers/gpu/drm/xe/xe_gt_debugfs.c

@@ -268,6 +268,13 @@ void xe_gt_debugfs_register(struct xe_gt *gt)
 		return;
 	}
 
+	/*
+	 * Store the xe_gt pointer as private data of the gt/ directory node
+	 * so other GT specific attributes under that directory may refer to
+	 * it by looking at its parent node private data.
+	 */
+	root->d_inode->i_private = gt;
+
 	/*
 	 * Allocate local copy as we need to pass in the GT to the debugfs
 	 * entry and drm_debugfs_create_files just references the drm_info_list