drm/i915: Drop check for non-NULL entry in llist_for_each_entry_safe

Since the next entry is an offset from a pointer, it can not be NULL.
For simplicity, drop the extra conditional before calling cond_resched()
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190530082358.13663-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gem/i915_gem_object.c

@@ -248,8 +248,7 @@ static void __i915_gem_free_objects(struct drm_i915_private *i915,
 		GEM_BUG_ON(!atomic_read(&i915->mm.free_count));
 		atomic_dec(&i915->mm.free_count);
 
-		if (on)
-			cond_resched();
+		cond_resched();
 	}
 	intel_runtime_pm_put(i915, wakeref);
 }