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: Ic9fd19570987c5c3d96d3a35f2d3e2c7ea4642d9
diff --git a/target/product/base_system.mk b/target/product/base_system.mk
index 7cc3270..41f6f22 100644
--- a/target/product/base_system.mk
+++ b/target/product/base_system.mk
@@ -16,8 +16,8 @@
 
 # Base modules and settings for the system partition.
 PRODUCT_PACKAGES += \
-    abb \
     adbd \
+    adbd_system_binaries \
     am \
     android.hidl.allocator@1.0-service \
     android.hidl.base-V1.0-java \