[Analysis] Remove a redundant const from a return type (NFC)

Identified with readability-const-return-type.

llvm/lib/Analysis/ScalarEvolution.cpp

@@ -3486,7 +3486,7 @@ const SCEV *ScalarEvolution::getUDivExpr(const SCEV *LHS,
   return S;
 }
-static const APInt gcd(const SCEVConstant *C1, const SCEVConstant *C2) {
+const APInt gcd(const SCEVConstant *C1, const SCEVConstant *C2) {
   APInt A = C1->getAPInt().abs();
   APInt B = C2->getAPInt().abs();
   uint32_t ABW = A.getBitWidth();