Remove unnecessary cast that was also unnecessarily casting away constness.

Even looking at the revision history I couldn't quite piece together why this
cast was ever written in the first place, but I assume it was because of some
change in the inheritance, perhaps this function was reimplemented in a
derived type & this caller was meant to get the base version (& it wasn't
virtual)?

llvm-svn: 162301

llvm/lib/CodeGen/RegAllocGreedy.cpp

@@ -1747,7 +1747,7 @@ unsigned RAGreedy::selectOrSplit(LiveInterval &VirtReg,
 bool RAGreedy::runOnMachineFunction(MachineFunction &mf) {
   DEBUG(dbgs() << "********** GREEDY REGISTER ALLOCATION **********\n"
                << "********** Function: "
-               << ((Value*)mf.getFunction())->getName() << '\n');
+               << mf.getFunction()->getName() << '\n');
 
   MF = &mf;
   if (VerifyEnabled)