[IR] Simplify Intrinsic::getDeclaration. NFC.

Author: jayfoad

llvm/lib/IR/Function.cpp

@@ -1423,9 +1423,8 @@ Function *Intrinsic::getDeclaration(Module *M, ID id, ArrayRef<Type*> Tys) {
   // because intrinsics must be a specific type.
   auto *FT = getType(M->getContext(), id, Tys);
   return cast<Function>(
-      M->getOrInsertFunction(Tys.empty() ? getName(id)
-                                         : getName(id, Tys, M, FT),
-                             getType(M->getContext(), id, Tys))
+      M->getOrInsertFunction(
+           Tys.empty() ? getName(id) : getName(id, Tys, M, FT), FT)
           .getCallee());
 }