Add support for passing '-target armv8' through the Driver.

llvm-svn: 184970
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 6d468ab..925a18f 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -528,6 +528,7 @@
     .Cases("armv7s", "armv7-s", "swift")
     .Cases("armv7r", "armv7-r", "cortex-r4")
     .Cases("armv7m", "armv7-m", "cortex-m3")
+    .Cases("armv8", "armv8a", "armv8-a", "cortex-a53")
     .Case("ep9312", "ep9312")
     .Case("iwmmxt", "iwmmxt")
     .Case("xscale", "xscale")