Use adbd_system_binaries to track adbd's dependencies.

required doesn't propagate from apexes, so we need a separate phony
target to track adbd's dependenecies.

Test: m
Change-Id: I4c97047dbd1c2f9b394d864aed229798f09fc9b1
diff --git a/Android.bp b/Android.bp
index 170053b..bf71919 100644
--- a/Android.bp
+++ b/Android.bp
@@ -513,6 +513,19 @@
     ],
 }
 
+phony {
+    name: "adbd_system_binaries",
+    required: [
+        "abb",
+    ]
+}
+
+phony {
+    name: "adbd_system_binaries_recovery",
+    required: [
+    ],
+}
+
 cc_binary {
     name: "static_adbd",
     defaults: ["adbd_defaults", "host_adbd_supported"],