wifi: iwlwifi: mvm: Fix race in scan completion

The move of the scan complete notification handling to the wiphy worker
introduced a race between scan complete notification and scan abort:

- The wiphy lock is held, e.g., for rfkill handling etc.
- Scan complete notification is received but not handled yet.
- Scan abort is triggered, and scan abort is sent to the FW. Once the
  scan abort command is sent successfully, the flow synchronously waits
  for the scan complete notification. However, as the scan complete
  notification was already received but not processed yet, this hangs for
  a second and continues leaving the scan status in an inconsistent
  state.
- Once scan complete handling is started (when the wiphy lock is not held)
  since the scan status is not an inconsistent state, a warning is issued
  and the scan complete notification is not handled.

To fix this issue, switch back the scan complete notification to be
asynchronously handling, and only move the link selection logic to
a worker (which was the original reason for the move to use wiphy lock).

While at it, refactor some prints to improve debug data.

Fixes: 07bf5297

 ("wifi: iwlwifi: mvm: Implement new link selection algorithm")
Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240506095953.1f484a86324b.I63ed445a47f144546948c74ae6df85587fdb4ce3@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>