[mlir][Linalg] NFC: Expose some utility functions used for promotion.

Exposing some utility functions from Linalg to allow for promotion of
fused views outside of the core tile+fuse logic.
This is an alternative to patch D91322 which adds the promotion logic
to the tileAndFuse method. Downside with that approach is that it is
not easily customizable based on needs.

Differential Revision: https://reviews.llvm.org/D91503