[BOLT][NFC] Simplify scanExternalRefs

[rafauler]

LGTM

bolt/lib/Core/BinaryFunction.cpp

for (uint64_t Offset = 0; Offset < getSize(); Offset += Size) {
     };
 
     // Detect if the instruction references an address.
     // Without relocations, we can only trust PC-relative address modes.
     uint64_t TargetAddress = 0;
     bool IsPCRel = false;
     bool IsBranch = false;
     if (BC.MIB->hasPCRelOperand(Instruction)) {
-      if (BC.MIB->evaluateMemOperandTarget(Instruction, TargetAddress,
-                                           AbsoluteInstrAddr, Size)) {
-        IsPCRel = true;
-      }
+      IsPCRel = BC.MIB->evaluateMemOperandTarget(Instruction, TargetAddress,
+                                                 AbsoluteInstrAddr, Size);
     } else if (BC.MIB->isCall(Instruction) || BC.MIB->isBranch(Instruction)) {
-      if (BC.MIB->evaluateBranch(Instruction, AbsoluteInstrAddr, Size,
-                                 TargetAddress)) {
-        IsBranch = true;
-      }
+      IsBranch = BC.MIB->evaluateBranch(Instruction, AbsoluteInstrAddr, Size,
+                                        TargetAddress);
     }
 
     MCSymbol *TargetSymbol = nullptr;
 
     // Create an entry point at reference address if needed.
     BinaryFunction *TargetFunction =
         BC.getBinaryFunctionContainingAddress(TargetAddress);
     if (TargetFunction && !ignoreFunctionRef(*TargetFunction)) {