Security overflow patch

[CoSunshine]

https://github.com/timi-liuliang/echo/blob/master/thirdparty/google/tensorflow/lite/kernels/embedding_lookup_sparse.cc#L146 is potential overflow when creating required bytes.

patched by developer:tensorflow/tensorflow@1de4972

[CoSunshine]

Similar, there is a race condition in function: https://github.com/timi-liuliang/echo/blob/master/thirdparty/google/tensorflow/lite/kernels/activations.cc#L1603

patched by tensorflow: tensorflow/tensorflow@ce8e286

[CoSunshine]

There is potential null pointer in this function: https://github.com/timi-liuliang/echo/blob/master/thirdparty/google/tensorflow/lite/kernels/add.cc#L87

general_scale_int16 = !params || !params->pot_scale_int16;

already be patched by tensorflow:
tensorflow/tensorflow@bbd2987