revert r179735, it has no testcases, and doesn't really make sense.

llvm-svn: 180574
diff --git a/llvm/lib/IR/AttributeImpl.h b/llvm/lib/IR/AttributeImpl.h
index b17aa43..8e9c30d 100644
--- a/llvm/lib/IR/AttributeImpl.h
+++ b/llvm/lib/IR/AttributeImpl.h
@@ -178,7 +178,7 @@
 
   unsigned getAlignment() const;
   unsigned getStackAlignment() const;
-  std::string getAsString(bool TargetIndependent, bool InAttrGrp) const;
+  std::string getAsString(bool InAttrGrp) const;
 
   typedef SmallVectorImpl<Attribute>::iterator       iterator;
   typedef SmallVectorImpl<Attribute>::const_iterator const_iterator;