[MLIR][Linalg] Retire C++ DotOp in favor of a linalg-ods-gen'd op

- replace DotOp, now that DRR rules have been dropped.

- Capture arguments mismatch in the parser. The number of parsed arguments must
  equal the number of expected arguments.

Reviewed By: ftynse, nicolasvasilache

Differential Revision: https://reviews.llvm.org/D82952