adb: Support 'adb enable/disable-verity' when using AVB.

Link with libavb_user and use this to enable/disable dm-verity if AVB
is in use.

Bug: 34124301
Test: Manually tested.
Change-Id: Ic03651312b955081cb3c126f6dafc46d6eeec0da
diff --git a/adb/Android.mk b/adb/Android.mk
index d17b063..112bc80 100644
--- a/adb/Android.mk
+++ b/adb/Android.mk
@@ -363,6 +363,7 @@
 LOCAL_STRIP_MODULE := keep_symbols
 LOCAL_STATIC_LIBRARIES := \
     libadbd \
+    libavb_user \
     libbase \
     libbootloader_message \
     libfs_mgr \