When STA is disconnected, ensure that the interface is in a cleanly stopped
state:
- if in regular enable/disable state, stop beacons if necessary
- in any other state, disable the interface
When the STA is up, ignore repeated start commands for the same channel, in
order to avoid unnecessary AP restarts
Signed-off-by: Felix Fietkau <nbd@nbd.name>
4acbe4e336