/bin/wifi:  Follow up to go/fibercl/71387.

Addresses comments in that code review:

- Call e.g. "iw dev wcli0" rather than "iw wcli0".
- Scan with AP interfaces rather than client interfaces (the latter of
  which may not always be present).
- Update the optstring to reflect that scan, like set and setclient,
  operates on only a single band.

Change-Id: Iee645c6b782971b65b58145fd34030f67a29dae0
2 files changed