[llvm] [mlir] Allowing RDV to call `getArgOperandsMutable()` (PR #160415)

[Francisco Geiman Thiesen via llvm-commits]

FranciscoThiesen wrote:

@joker-eph @kuhar ADT functionality was merged, can I get a re-review here? https://github.com/llvm/llvm-project/commit/d8a296523af503327c86252daaf6a57898e503c1

https://github.com/llvm/llvm-project/pull/160415