The scan code unlocks the comlock and calls into the driver. It then
assumes the state hasn't changed from underneath it.
Although I haven't seen this particular condition trigger, I'd like to
be informed if I or anyone else sees it.
What I'm thinking may occur:
* A cancellation comes in during the scan_end call;
* the cancel flag is set;
* but it's never checked, so scandone isn't updated;
* .. and the interface stays in the STA power save mode.
It's a subtle race, if it even exists.
PR: kern/163318
66b74386c7