message: Added missing bf16 registration for sparse_xent_op
diff: @@ -122,6 +122,8 @@ REGISTER(CPU, float, int32)
  REGISTER(CPU, float, int64)
  REGISTER(CPU, double, int32)
  REGISTER(CPU, double, int64)
  +REGISTER(CPU, Eigen::bfloat16, int32)
  +REGISTER(CPU, Eigen::bfloat16, int64)
  REGISTER(CPU, Eigen::half, int32)
  REGISTER(CPU, Eigen::half, int64)
  