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>

[ROCm/composable_kernel commit: 0345963eef]

library/src/utility/host_tensor.cpp

@@ -31,6 +31,9 @@ std::size_t HostTensorDescriptor::GetElementSpaceSize() const
     std::size_t space = 1;
     for(std::size_t i = 0; i < mLens.size(); ++i)
     {
+        if(mLens[i] == 0)
+            continue;
+
         space += (mLens[i] - 1) * mStrides[i];
     }
     return space;