[mlir] Introduce AlignmentAttrOpInterface to expose MaybeAlign (#161440)
Introduce a common interface for operations with alignment attributes
across MemRef, Vector, and SPIRV dialects. The interface exposes
getMaybeAlign() to retrieve alignment as llvm::MaybeAlign.
This is the second part of the PRs addressing issue #155677.
Co-authored-by: Erick Ochoa Lopez <erick.ochoalopez@amd.com>