drm/xe/display: remove unused xe->sb_lock

Nothing in xe needs xe->sb_lock. None of the i915 display code using
->sb_lock gets built with xe, and in any case that would be wrong as xe
uses gt->pcode.lock for this.
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240510094313.3422982-2-jani.nikula@intel.comSigned-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/xe/display/xe_display.c

@@ -96,8 +96,6 @@ int xe_display_create(struct xe_device *xe)
 
 	xe->display.hotplug.dp_wq = alloc_ordered_workqueue("xe-dp", 0);
 
-	drmm_mutex_init(&xe->drm, &xe->sb_lock);
-
 	return drmm_add_action_or_reset(&xe->drm, display_destroy, NULL);
 }
 

drivers/gpu/drm/xe/xe_device_types.h

@@ -499,9 +499,6 @@ struct xe_device {
 	/* To shut up runtime pm macros.. */
 	struct xe_runtime_pm {} runtime_pm;
 
-	/* For pcode */
-	struct mutex sb_lock;
-
 	/* only to allow build, not used functionally */
 	u32 irq_mask;