[mlir][nvvm] Fix support for tf32 data type in mma.sync

The NVVM dialect test coverage for all possible type/shape combinations
in the `nvvm.mma.sync` op is mostly complete. However, there were tests
missing for TF32 datatype support. This change adds tests for the one
relevant shape/type combination. This uncovered a small bug in the op
verifier, which this change also fixes.

Differential Revision: https://reviews.llvm.org/D124975