move fastcall/stdcall mangling up into Mangler.

llvm-svn: 98384
diff --git a/llvm/lib/MC/MCAsmInfoCOFF.cpp b/llvm/lib/MC/MCAsmInfoCOFF.cpp
index 9130493..5170206 100644
--- a/llvm/lib/MC/MCAsmInfoCOFF.cpp
+++ b/llvm/lib/MC/MCAsmInfoCOFF.cpp
@@ -35,4 +35,5 @@
   AbsoluteEHSectionOffsets = false;
   SupportsDebugInformation = true;
   DwarfSectionOffsetDirective = "\t.secrel32\t";
+  HasMicrosoftFastStdCallMangling = true;
 }