Add telephony sources to hiddenapi-mappings

This makes it possible to annotate telephony greylisted apis in
frameworks/opt/telephony.

Test: m hiddenapi-mappings
Bug: 110868826
Change-Id: I1f7d2722bd7621c9f6d1195ea212a7a0454d560d
diff --git a/Android.bp b/Android.bp
index f4e8b63..a3d3fd4 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1664,6 +1664,7 @@
     srcs: [
         ":openjdk_java_files",
         ":non_openjdk_java_files",
+        ":opt-telephony-common-srcs",
     ],
     arg_files: [
         "core/res/AndroidManifest.xml",