Add libnetd_updatable to tethering-module-sdk

System libraries and binaries (e.g. netd) have a dependency on this.
Adding it to the sdk module allows an external snapshotting script
to generate prebuilts stubs of this library and commit them to
prebuilts/module_sdk. This allows minimal branch setup to build against
the apis of libnetd_updatable without checking out its source code.

Bug: 273723791
Test: m tethering-module-sdk
Change-Id: I1f235d86abba2c37ca7d750dea7071227e1346fe
1 file changed