[mlir][sparse] use shared util for DimOp generation

This shares more code with existing utilities. Also, to be consistent,
we moved dimension permutation on the DimOp to the tensor lowering phase.
This way, both pre-existing DimOps on sparse tensors (not likely but
possible) as well as compiler generated DimOps are handled consistently.

Reviewed By: bixia

Differential Revision: https://reviews.llvm.org/D108309