remove discourse link from comment

Author: ro-i

llvm/lib/Transforms/Scalar/StructurizeCFG.cpp

@@ -1398,8 +1398,7 @@ bool StructurizeCFG::run(Region *R, DominatorTree *DT,
                          const TargetTransformInfo *TTI) {
   // CallBr and its corresponding direct target blocks are for now ignored by
   // this pass. This is not a limitation for the currently intended uses cases
-  // of callbr in the AMDGPU backend (cf.
-  // https://discourse.llvm.org/t/rfc-add-callbr-intrinsic-support/86087).
+  // of callbr in the AMDGPU backend.
   // Parent and child regions are not affected by this (current) restriction.
   // See `llvm/test/Transforms/StructurizeCFG/callbr.ll` for details.
   if (R->isTopLevelRegion() || isa<CallBrInst>(R->getEntry()->getTerminator()))