[TOSA] Update TOSA's rounding mode, nan propagation and resize mode to enums

[justin-ngo-arm]

Context: TOSA's rounding mode, nan propagation, and resize mode have been updated from string attributes to enums.

This commit updates the Torch to TOSA path to align with those changes.

[justin-ngo-arm]

Hi @vivekkhandelwal1, next time that you bump LLVM within Torch-MLIR, you will find that there are TOSA-related breaking changes. The updates included in this PR should help you resolve those breakages. I tried to bump the LLVM version in Torch-MLIR myself, but there were some other non-TOSA related issues that I didn't have the bandwidths to look into, so I only worked on a fix the TOSA ones.