[AMD] Refactor kWidth Assignment into Separate Logic

[christopherpriebe]

Refactored kWidth assignment into separate logic from the MFMA intrinsic logic.

For now, the logic has been refactored into separate rewrite rules. However, the logic could feasibly be refactored into a separate pass as well; I tried this initially but ran into some issues.

Two things:

• I don't want to use the function isChainDot if possible, but I haven't figured out a way to detect the chain dot scenario; if someone has a better way centered around the ConvertLayout operation, please let me know.
• I tried to refactor out the scaled dot kWidth logic as well, but it isn't as simple as the normal dot kWidth logic. The logic is 1) centered around properties directly associated with the scaled dot operation and 2) needs to be propagated it seems through other IR constructs. When I tried doing this same logic separately, it caused a lot of failures.