fix scale pack4

src/layer/vulkan/scale_vulkan.cpp

@@ -105,9 +105,9 @@ int Scale_vulkan::create_pipeline(const Option& opt)
         // pack8
         if ((opt.use_shader_pack8 && shape.dims == 0) || elempack == 8)
         {
-            pipeline_scale_pack4 = new Pipeline(vkdev);
-            pipeline_scale_pack4->set_optimal_local_size_xyz(local_size_xyz);
-            pipeline_scale_pack4->create("scale_pack8", opt, specializations, 3, 5);
+            pipeline_scale_pack8 = new Pipeline(vkdev);
+            pipeline_scale_pack8->set_optimal_local_size_xyz(local_size_xyz);
+            pipeline_scale_pack8->create("scale_pack8", opt, specializations, 3, 5);
         }
 
         return 0;