Fix buildbreak introduced in ed2deab

Author: mtrofin

llvm/lib/CodeGen/MLRegallocEvictAdvisor.cpp

@@ -58,10 +58,10 @@ static cl::opt<std::string> ModelUnderTraining(
     "regalloc-model", cl::Hidden,
     cl::desc("The model being trained for register allocation eviction"));
 
-extern cl::opt<unsigned> EvictInterferenceCutoff;
-
 #endif // #ifdef LLVM_HAVE_TF_API
 
+extern cl::opt<unsigned> EvictInterferenceCutoff;
+
 /// The score injection pass.
 /// This pass calculates the score for a function and inserts it in the log, but
 /// this happens only in development mode. It's a no-op otherwise.