[TOSA] Add int8 and int16 legalization of the EXP op
Hi @rsuderman, Can you please review this PR ? Thank you! Hi @Tessil Can you please resolve conflicts? Thank you! Hi @Tessil Can you please resolve conflicts? Thank you! This PR is stale because it has been open for 14 days with no activity. It will be closed if no further activity occurs. Thank you. This PR was closed because it has been inactive for 14 days since being marked as stale. Please reopen if you'd like to work on this further.
Hi,

This PR adds int8 and int16 TFL -> TOSA legalization for the EXP operator. 

It also contains a commit to align `getTosaConst8bitTable` and `getTosaConst16bitTable` to [LUTPopulate](https://github.com/tensorflow/tensorflow/blob/72aa8ab84e24f66762e502ba6f39f12587e2415b/tensorflow/lite/kernels/internal/common.h#L494) to ensure the generated LUT is bit-exact during legalization.

Thibaut