art: Handle x86_64 architecture equal to x86

This patch forces FE/ME to treat x86_64 as x86 exactly.
The x86_64 logic will be revised later when assembly will be ready.

Change-Id: I4a92477a6eeaa9a11fd710d35c602d8d6f88cbb6
Signed-off-by: Dmitry Petrochenko <dmitry.petrochenko@intel.com>
diff --git a/compiler/driver/compiler_driver.cc b/compiler/driver/compiler_driver.cc
index a120d05..4f3533a 100644
--- a/compiler/driver/compiler_driver.cc
+++ b/compiler/driver/compiler_driver.cc
@@ -2015,6 +2015,11 @@
       *target_attr = "";
       break;
 
+    case kX86_64:
+      *target_triple = "x86_64-pc-linux-gnu";
+      *target_attr = "";
+      break;
+
     case kMips:
       *target_triple = "mipsel-unknown-linux";
       *target_attr = "mips32r2";