Retype from unsigned to CallingConv::ID accordingly. Approved by Bob Wilson.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80773 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/CBackend/CBackend.cpp

@@ -2283,6 +2283,8 @@ void CWriter::printFunctionSignature(const Function *F, bool Prototype) {
    case CallingConv::X86_FastCall:
     Out << "__attribute__((fastcall)) ";
     break;
+   default:
+    break;
   }
   
   // Loop over the arguments, printing them...