[clang] [CIR] Add calling_conv attribute to FuncOp with lowering support (PR #189345)

[Rana Pratap Reddy via cfe-commits]

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@@ -71,7 +71,6 @@ struct MissingFeatures {
   static bool opFuncArmNewAttr() { return false; }
   static bool opFuncArmStreamingAttr() { return false; }
   static bool opFuncAstDeclAttr() { return false; }
-  static bool opFuncCallingConv() { return false; }
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ranapratap55 wrote:

Restored `opFuncCallingConv()`.

https://github.com/llvm/llvm-project/pull/189345