[clang] [clang][Driver] Use the bare-metal toolchain for LoongArch (PR #223703)

[Weining Lu via cfe-commits]

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@@ -55,6 +55,12 @@ static bool isX86BareMetal(const llvm::Triple &Triple) {
          Triple.getEnvironmentName() == "elf";
 }
 
+/// Is the triple loongarch{32,64}-*-none-elf?
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SixWeining wrote:

I think we can merge the fix first, and consider updating the documentation later.

https://github.com/llvm/llvm-project/pull/223703