[NFC] [hwasan] remove unused method

Author: fmayer

llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp

@@ -316,7 +316,6 @@ class HWAddressSanitizer {
     Value *PtrTag = nullptr;
     Value *MemTag = nullptr;
   };
-  void setSSI(const StackSafetyGlobalInfo *S) { SSI = S; }
 
   void initializeModule();
   void createHwasanCtorComdat();