[llvm] TargetSchedule: factor out code in computeOperandLatency (NFC) (PR #73769)

[Francesco Petrogalli via llvm-commits]

https://github.com/fpetrogalli commented:

Thank you for the patch.

Just some minor nits, plus a couple of comment about some follow up (or prep) work that I think would improve the TII method for retrieving the latency of an operand . Consider the TII interface chance as "nice to have", I will not hold the patch on it.

Francesco

https://github.com/llvm/llvm-project/pull/73769