Changed sign of LastCallToStaticBouns

Summary:
I think it is much better this way.
When I firstly saw line:
  Cost += InlineConstants::LastCallToStaticBonus;
I though that this is a bug, because everywhere where the cost is being reduced
it is usuing -=.

Reviewers: eraman, tejohnson, mehdi_amini

Subscribers: llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D23222

llvm-svn: 278290
diff --git a/llvm/lib/Analysis/InlineCost.cpp b/llvm/lib/Analysis/InlineCost.cpp
index dd9174c..c0ac6c8 100644
--- a/llvm/lib/Analysis/InlineCost.cpp
+++ b/llvm/lib/Analysis/InlineCost.cpp
@@ -1257,7 +1257,7 @@
   bool OnlyOneCallAndLocalLinkage =
       F.hasLocalLinkage() && F.hasOneUse() && &F == CS.getCalledFunction();
   if (OnlyOneCallAndLocalLinkage)
-    Cost += InlineConstants::LastCallToStaticBonus;
+    Cost -= InlineConstants::LastCallToStaticBonus;
 
   // If this function uses the coldcc calling convention, prefer not to inline
   // it.