Add tethering-module-sdk build target.

Bug: 177884752
Test: m tethering-module-sdk
Change-Id: Idd4e6743001a6402f6a5dd6832601b08d7cc0236
diff --git a/Tethering/Android.bp b/Tethering/Android.bp
index 73175580..62e82da 100644
--- a/Tethering/Android.bp
+++ b/Tethering/Android.bp
@@ -145,3 +145,10 @@
     apex_available: ["com.android.tethering"],
     min_sdk_version: "30",
 }
+
+sdk {
+    name: "tethering-module-sdk",
+    java_sdk_libs: [
+        "framework-tethering",
+    ],
+}