Example of Matmul implementation in linalg.generic operation contained few mistakes that can puzzle new startes when trying to run the example.
Differential Revision: https://reviews.llvm.org/D82289
And can be reused in multiple places as:
```mlir
linalg.generic #matmul_trait %A, %B, %C [other-attributes] {
- (%a: f32, %b: f32, %c: f32) :
+ ^bb0(%a: f32, %b: f32, %c: f32) :
%d = mulf %a, %b: f32
%e = addf %c, %d: f32
- linalg_yield %e : f32
+ linalg.yield %e : f32
} : memref<?x?xf32, stride_specification>,
memref<?x?xf32, stride_specification>,
memref<?x?xf32, stride_specification>