[CodeGen] Don't explicitly set intrinsic attributes (NFCI)

The intrinsic attributes are automatically set when the function
is created, there is no need to assign them explicitly.

Author: nikic

clang/lib/CodeGen/CodeGenModule.cpp

@@ -2936,9 +2936,8 @@ void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, llvm::Function *F,
                                           bool IsThunk) {
 
   if (llvm::Intrinsic::ID IID = F->getIntrinsicID()) {
-    // If this is an intrinsic function, set the function's attributes
-    // to the intrinsic's attributes.
-    F->setAttributes(llvm::Intrinsic::getAttributes(getLLVMContext(), IID));
+    // If this is an intrinsic function, the attributes will have been set
+    // when the function was created.
     return;
   }