Fix build error on darwin_arm64

Change-Id: Ie5bc9252de8349c3bfb8269919c0a173a9d9cc2d
diff --git a/libc/Android.bp b/libc/Android.bp
index 6ca9503..f5f5f7c 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -1852,8 +1852,8 @@
         hwaddress: true,
     },
     enabled: false,
-    arch: {
-        arm64: {
+    target: {
+        android_arm64: {
             enabled: true,
         },
     },