[Math] Don't exclude TMath::Limits<Long64_t> functions from LinkDef

Some link pragmas were commented out because they supposedly don't work
with CINT. This is not applicable anymore.

One might consider to just remove these pragmas because
`link C++ function` is ignored now, but for consistency with the
previous lines that list the functions for different types, I would
suggest to keep it.

Author: guitargeek

math/mathcore/inc/LinkDef1.h

@@ -35,9 +35,8 @@
 #pragma link C++ function TMath::Limits<Int_t>::Max();
 #pragma link C++ function TMath::Limits<Int_t>::Min();
 
-// exclude these since they do not work in Cling
-//#pragma link C++ function TMath::Limits<Long64_t>::Max();
-//#pragma link C++ function TMath::Limits<Long64_t>::Min();
+#pragma link C++ function TMath::Limits<Long64_t>::Max();
+#pragma link C++ function TMath::Limits<Long64_t>::Min();
 
 #pragma link C++ function TMath::MinElement(Long64_t, const Short_t*);
 #pragma link C++ function TMath::MinElement(Long64_t, const Int_t*);