Add libasyncio.

libadbd_usb depends on libasyncio.

Bug: 37916658
Test: Use adb in recovery on bullhead/marlin
Change-Id: I77ac3bb2a580d29551e7b5c471bc3cfbf1a3219d
diff --git a/Android.mk b/Android.mk
index dc066dd..c35dabc 100644
--- a/Android.mk
+++ b/Android.mk
@@ -127,6 +127,7 @@
     libmounts \
     libz \
     libminadbd \
+    libasyncio \
     libfusesideload \
     libminui \
     libpng \