[clang] [Driver] Add options to control workaround for Cortex-A53 Erratum 843419 (PR #143915)

[Bryan Chan via cfe-commits]

================
@@ -91,7 +91,9 @@ void fuchsia::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("--execute-only");
 
     std::string CPU = getCPUName(D, Args, Triple);
-    if (CPU.empty() || CPU == "generic" || CPU == "cortex-a53")
+    if (Args.hasFlag(options::OPT_mfix_cortex_a53_843419,
+                     options::OPT_mno_fix_cortex_a53_843419, true) &&
----------------
bryanpkc wrote:

The GCC docs say that these options are "ignored if an architecture or cpu is specified on the command line which does not need the workaround". So I think what we have in this PR mostly matches that description.

I could submit a new PR to add a condition to check whether the architecture is armv8.1-a or later.

https://github.com/llvm/llvm-project/pull/143915