Manually unroll MDS calculation

[georgeee]

Modify full_round to perform round inline when params.mds.len() == 3.

This optimization gave a ~3% speedup (measured by mina ledger test apply on top of a PR stack #2394, https://github.com/MinaProtocol/mina/pull/15980 and TODO open a PR.

Although 3% isn't much, I expect speed-up to be better when a batch version of hash (https://github.com/MinaProtocol/mina/issues/16053) is delivered.

P.S. change's diff is bloated by ^M characters present at the end of each line for the previous version of the poseidon/src/permutation.rs file.