Add MNK padding, M = 0 support into grouped_gemm (#539)
* add mnk padding, support m=0
* clean code
* clean code
Co-authored-by:
Rostyslav Geyyer <46627076+geyyer@users.noreply.github.com>
* add mnk padding, support m=0
* clean code
* clean code
Co-authored-by:
Rostyslav Geyyer <46627076+geyyer@users.noreply.github.com>