[ARM64] Plumb in big-endian - add arm64_be to the many switches where it was missing.

llvm-svn: 206462
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index c7a0919..be83713 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -1873,6 +1873,8 @@
         Target.setArch(llvm::Triple::mips64el);
       else if (Target.getArch() == llvm::Triple::aarch64_be)
         Target.setArch(llvm::Triple::aarch64);
+      else if (Target.getArch() == llvm::Triple::arm64_be)
+        Target.setArch(llvm::Triple::arm64);
     } else {
       if (Target.getArch() == llvm::Triple::mipsel)
         Target.setArch(llvm::Triple::mips);
@@ -1880,6 +1882,8 @@
         Target.setArch(llvm::Triple::mips64);
       else if (Target.getArch() == llvm::Triple::aarch64)
         Target.setArch(llvm::Triple::aarch64_be);
+      else if (Target.getArch() == llvm::Triple::arm64)
+        Target.setArch(llvm::Triple::arm64_be);
     }
   }