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).

llvm-svn: 162367
diff --git a/llvm/lib/CodeGen/CalcSpillWeights.cpp b/llvm/lib/CodeGen/CalcSpillWeights.cpp
index 5045675..bc5258e 100644
--- a/llvm/lib/CodeGen/CalcSpillWeights.cpp
+++ b/llvm/lib/CodeGen/CalcSpillWeights.cpp
@@ -41,8 +41,7 @@
 bool CalculateSpillWeights::runOnMachineFunction(MachineFunction &MF) {
 
   DEBUG(dbgs() << "********** Compute Spill Weights **********\n"
-               << "********** Function: "
-               << MF.getName() << '\n');
+               << "********** Function: " << MF.getName() << '\n');
 
   LiveIntervals &LIS = getAnalysis<LiveIntervals>();
   MachineRegisterInfo &MRI = MF.getRegInfo();