Convert android.hardware.light@2.0 to soong.

Convert both the *-impl.so and the *-service to be built with Soong
instead of make.

Test: cd hardware/interfaces/light && mma -j60
Bug: 37512442
Change-Id: I15c4779a7c9eea39fb20746f69800dcf20670275
diff --git a/light/Android.bp b/light/Android.bp
index 8d2c986..654bb80 100644
--- a/light/Android.bp
+++ b/light/Android.bp
@@ -1,5 +1,6 @@
 // This is an autogenerated file, do not edit.
 subdirs = [
     "2.0",
+    "2.0/default",
     "2.0/vts/functional",
 ]