Update list of allowed aarch64 features

These features were recently added to std_detect. Features not supported
by LLVM 9, the current minimum version for Rust, are commented.

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -152,6 +152,12 @@ pub fn to_llvm_feature<'a>(sess: &Session, s: &'a str) -> &'a str {
         ("x86", "avx512vpclmulqdq") => "vpclmulqdq",
         ("aarch64", "fp") => "fp-armv8",
         ("aarch64", "fp16") => "fullfp16",
+        ("aarch64", "fhm") => "fp16fml",
+        ("aarch64", "lse2") => "outline-atomics",
+        ("aarch64", "rcpc2") => "rcpc-immo",
+        ("aarch64", "dpb") => "ccpp",
+        ("aarch64", "dpb2") => "ccdp",
+        ("aarch64", "fcma") => "complxnum",
         (_, s) => s,
     }
 }