Provide the register scavenger to processFunctionBeforeFrameFinalized

Add the current PEI register scavenger as a parameter to the
processFunctionBeforeFrameFinalized callback.

This change is necessary in order to allow the PowerPC target code to
set the register scavenger frame index after the save-area offset
adjustments performed by processFunctionBeforeFrameFinalized. Only
after these adjustments have been made is it possible to estimate
the size of the stack frame.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177108 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCFrameLowering.cpp b/lib/Target/PowerPC/PPCFrameLowering.cpp
index a93c944..6feec9f 100644
--- a/lib/Target/PowerPC/PPCFrameLowering.cpp
+++ b/lib/Target/PowerPC/PPCFrameLowering.cpp
@@ -841,8 +841,8 @@
     }
 }
 
-void PPCFrameLowering::processFunctionBeforeFrameFinalized(MachineFunction &MF)
-                                                                        const {
+void PPCFrameLowering::processFunctionBeforeFrameFinalized(MachineFunction &MF,
+                                                         RegScavenger *) const {
   // Early exit if not using the SVR4 ABI.
   if (!Subtarget.isSVR4ABI())
     return;