rustc_target: Add the 32s target feature for LoongArch

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -277,6 +277,7 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> Option<LLVMFea
         {
             None
         }
+        ("loongarch32" | "loongarch64", "32s") if get_version().0 < 21 => None,
         // Filter out features that are not supported by the current LLVM version
         ("riscv32" | "riscv64", "zacas") if get_version().0 < 20 => None,
         (