Delete unused function in Types.h (#4116)

Summary:
Pull Request resolved: #4116

TSIA
ghstack-source-id: 232319219
exported-using-ghexport

Reviewed By: SS-JIA

Differential Revision: D59281545

fbshipit-source-id: 98fe615b8ca73eafff6ff54003d59210a91efc83

Author: jorgep31415

backends/vulkan/runtime/api/Types.h

@@ -201,15 +201,6 @@ static constexpr GPUMemoryLayout kHeightPacked =
 static constexpr GPUMemoryLayout kChannelsPacked =
     GPUMemoryLayout::TENSOR_CHANNELS_PACKED;
 
-/*
- * Given a GPUMemoryLayout, return the index of the dimension that is packed
- * along texels, assuming WHCN dimension order.
- */
-template <typename T>
-T to_packed_dim_whcn_idx(const GPUMemoryLayout layout) {
-  return static_cast<T>(layout);
-}
-
 /*
  * Given a GPUMemoryLayout, return an offset that can be used to determine the
  * index of the dimension that is packed along texels, assuming NCHW dimension