MachineFunction: Return reference for getFrameInfo(); NFC

getFrameInfo() never returns nullptr so we should use a reference
instead of a pointer.

llvm-svn: 277017
diff --git a/llvm/lib/CodeGen/RegAllocFast.cpp b/llvm/lib/CodeGen/RegAllocFast.cpp
index 55fb33e..d3dcb4f7 100644
--- a/llvm/lib/CodeGen/RegAllocFast.cpp
+++ b/llvm/lib/CodeGen/RegAllocFast.cpp
@@ -209,8 +209,8 @@
     return SS;          // Already has space allocated?
 
   // Allocate a new stack object for this spill location...
-  int FrameIdx = MF->getFrameInfo()->CreateSpillStackObject(RC->getSize(),
-                                                            RC->getAlignment());
+  int FrameIdx = MF->getFrameInfo().CreateSpillStackObject(RC->getSize(),
+                                                           RC->getAlignment());
 
   // Assign the slot.
   StackSlotForVirtReg[VirtReg] = FrameIdx;