[CFL-AA] Remove unneeded function declaration. NFCI.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306268 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/CFLSteensAliasAnalysis.cpp

@@ -80,9 +80,6 @@ public:
   const AliasSummary &getAliasSummary() const { return Summary; }
 };
 
-/// Try to go from a Value* to a Function*. Never returns nullptr.
-static Optional<Function *> parentFunctionOfValue(Value *);
-
 const StratifiedIndex StratifiedLink::SetSentinel =
     std::numeric_limits<StratifiedIndex>::max();