iwl3945: queue the right work if the scan needs to be aborted

iwl3945's scan_completed calls into the mac80211 stack which triggers a
warn on if there is no scan outstanding.

This can be avoided by not calling scan_completed but abort_scan in
iwl3945_request_scan  in the done: branch of the function which is used
as an error out.

The done: branch seems to be an error-out branch, as, for example, if
iwl_is_ready(priv) returns false  the done: branch is executed.

NOTE:
I'm not familiar with the driver at all.
I just quickly scanned as a reaction to

https://bugzilla.kernel.org/show_bug.cgi?id=17722



the users of scan_completed in the  iwl3945 driver and noted the odd
discrepancy between the comment above this instance and the comment in
mac80211 scan_completed function.

Signed-off-by: Florian Mickler <florian@mickler.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>