Migrate all of aarch64-linux-gnu to \01_mcount instead of just when passing along gnueabi as this matches both gcc and what the kernel expects.

More of PR27311

llvm-svn: 296490
diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index da37a88..3616baf 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -5985,8 +5985,9 @@
     // AArch64 targets default to using the ARM C++ ABI.
     TheCXXABI.set(TargetCXXABI::GenericAArch64);
 
-    if (Triple.getOS() == llvm::Triple::Linux ||
-        Triple.getOS() == llvm::Triple::UnknownOS)
+    if (Triple.getOS() == llvm::Triple::Linux)
+      this->MCountName = "\01_mcount";
+    else if (Triple.getOS() == llvm::Triple::UnknownOS)
       this->MCountName = Opts.EABIVersion == "gnu" ? "\01_mcount" : "mcount";
   }