WifiServiceImpl: add tethering check for LOHS

Before starting up local only hotspot, first make sure we aren't already
tethering.  If we are, return null since it is not a valid mode change.
If not, continue to throw UnsupportedOperationException.

Bug: 36765661
Test: frameworks/opt/net/wifi/tests/wifitests/runtests.sh
Change-Id: I9a371c4c8ecbbcc658ab8dd844f87b8705bced3c
2 files changed
tree: cb762007eaa6a047a51b6324c2ce9ee2b9d9bc5a
  1. service/
  2. PREUPLOAD.cfg