avoid 'mips' namespace collision with <built-in> on mips64

Index: layers/best_practices_utils.cpp
--- layers/best_practices_utils.cpp.orig
+++ layers/best_practices_utils.cpp
@@ -376,8 +376,8 @@ IMAGE_STATE_BP* BestPractices::GetImageUsageState(VkIm
         auto image = Get<IMAGE_STATE>(vk_image);
         state.image = image.get();
         state.usages.resize(image->createInfo.arrayLayers);
-        for (auto& mips : state.usages) {
-            mips.resize(image->createInfo.mipLevels, IMAGE_SUBRESOURCE_USAGE_BP::UNDEFINED);
+        for (auto& vk_mips : state.usages) {
+            vk_mips.resize(image->createInfo.mipLevels, IMAGE_SUBRESOURCE_USAGE_BP::UNDEFINED);
         }
         return &state;
     }
