[mlir][NVVM] Add support for nvvm mma.sync ops

This patch adds MLIR NVVM support for the various NVPTX `mma.sync`
operations. There are a number of possible data type, shape,
and other attribute combinations supported by the operation, so a
custom assebmly format is added and attributes are inferred where
possible.

Reviewed By: ThomasRaoux

Differential Revision: https://reviews.llvm.org/D122410