[mlir] Remove old "tc" linalg ods generator.

* This could have been removed some time ago as it only had one op left in it, which is redundant with the new approach.
* `matmul_i8_i8_i32` (the remaining op) can be trivially replaced by `matmul`, which natively supports mixed precision.

Differential Revision: https://reviews.llvm.org/D110792