[AVR] Update data layout to match current LLVM trunk

The data layout was changed in r314179 to fix atomic loads and stores.

llvm-svn: 314354
diff --git a/clang/lib/Basic/Targets/AVR.h b/clang/lib/Basic/Targets/AVR.h
index 80c33e8..679e639 100644
--- a/clang/lib/Basic/Targets/AVR.h
+++ b/clang/lib/Basic/Targets/AVR.h
@@ -56,8 +56,7 @@
     WIntType = SignedInt;
     Char32Type = UnsignedLong;
     SigAtomicType = SignedChar;
-    resetDataLayout("e-p:16:16:16-i8:8:8-i16:16:16-i32:32:32-i64:64:64"
-                    "-f32:32:32-f64:64:64-n8");
+    resetDataLayout("e-p:16:8-i8:8-i16:8-i32:8-i64:8-f32:8-f64:8-n8-a:8");
   }
 
   void getTargetDefines(const LangOptions &Opts,