wpa: Reconnect ndis_events build

ndis_events build was disconnected by the MFC of
25ecdc7d52770caf1c9b44b5ec11f468f6b636f3.
Reconnect it.

This is a direct commit to stable/12.

Reported by: scott-allendorf@uiowa.edu>
Fixes: 5654815fd3604e024eefdcb34904d3a7c883e8c5