rustc_codegen_llvm: Simplify avx10.2 conversion

The original two match clauses represented `if` and `else` cases.
This commit replaces them into a single match clause with `bool::then()`.

Author: a4lg

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -305,8 +305,7 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> Option<LLVMFea
         }
         ("x86", "movrs") if major < 20 => None,
         ("x86", "avx10.1") => Some(LLVMFeature::new("avx10.1-512")),
-        ("x86", "avx10.2") if major < 20 => None,
-        ("x86", "avx10.2") if major >= 20 => Some(LLVMFeature::new("avx10.2-512")),
+        ("x86", "avx10.2") => (major >= 20).then(|| LLVMFeature::new("avx10.2-512")),
         ("x86", "apxf") => Some(LLVMFeature::with_dependencies(
             "egpr",
             smallvec![