Tidy up a few more uses of MF.getFunction()->getName().

Based on CR feedback from r162301 and Craig Topper's refactoring in r162347
here are a few other places that could use the same API (& in one instance drop
a Function.h dependency).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162367 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/LiveIntervalAnalysis.cpp

@@ -382,8 +382,7 @@ void LiveIntervals::handleRegisterDef(MachineBasicBlock *MBB,
 /// which a variable is live
 void LiveIntervals::computeIntervals() {
   DEBUG(dbgs() << "********** COMPUTING LIVE INTERVALS **********\n"
-               << "********** Function: "
-               << ((Value*)MF->getFunction())->getName() << '\n');
+               << "********** Function: " << MF->getName() << '\n');
 
   RegMaskBlocks.resize(MF->getNumBlockIDs());