drm/i915/execlists: Reduce list_for_each_safe+list_safe_reset_next

After staring at the list_for_each_safe macros for a bit, our current
invocation of list_safe_reset_next in execlists_schedule() simply
reduces to list_for_each.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180102151235.3949-11-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_lrc.c

@@ -1029,7 +1029,7 @@ static void execlists_schedule(struct drm_i915_gem_request *request, int prio)
 	 * end result is a topological list of requests in reverse order, the
 	 * last element in the list is the request we must execute first.
 	 */
-	list_for_each_entry_safe(dep, p, &dfs, dfs_link) {
+	list_for_each_entry(dep, &dfs, dfs_link) {
 		struct i915_priotree *pt = dep->signaler;
 
 		/*
@@ -1048,8 +1048,6 @@ static void execlists_schedule(struct drm_i915_gem_request *request, int prio)
 			if (prio > READ_ONCE(p->signaler->priority))
 				list_move_tail(&p->dfs_link, &dfs);
 		}
-
-		list_safe_reset_next(dep, p, dfs_link);
 	}
 
 	/*