message: Fix recent cmgen KTX regression.
  This fixes a KTX sizing bug that I introduced while incorporating code
  review feedback.
diff: @@ -964,7 +964,7 @@ static void saveImage(const std::string& path, ImageEncoder::Format format, cons
  }
  static void exportKtxFaces(KtxBundle& container, uint32_t miplevel, const Cubemap& cm) {
  - const uint32_t dim = cm.getDimensions() >> miplevel;
  + const uint32_t dim = cm.getDimensions();
  for (uint32_t j = 0; j < 6; j++) {
  KtxBlobIndex blobIndex {(uint32_t) miplevel, 0, j};
  Cubemap::Face face;
  