[llvm] [VPlan] Remove unused first mask op from VPBlendRecipe. (PR #87770)

[via llvm-commits]

================
@@ -1951,13 +1951,18 @@ class VPBlendRecipe : public VPSingleDefRecipe {
 
   /// Return the number of incoming values, taking into account that a single
   /// incoming value has no mask.
----------------
ayalz wrote:

```suggestion
  /// Return the number of incoming values, taking into account that the first
  /// incoming value has no mask.
```

https://github.com/llvm/llvm-project/pull/87770