Add default implementation of Vibrator HAL

Test: Builds, boots, vibrator works on bullhead
Change-Id: I9c7de913d1b565bdc46a3b99a799fd8ba09b06a4
diff --git a/Android.bp b/Android.bp
index 3cf3b3b..c69caf0 100644
--- a/Android.bp
+++ b/Android.bp
@@ -12,4 +12,5 @@
     "tests/pointer/1.0",
     "wifi/1.0",
     "wifi/supplicant/1.0",
+    "vibrator/1.0",
 ]