ath10k: fix inconsistent survey reports

In some cases some channel survey data was
reported incorrect.

Channel info events were expected to come in pairs
without and with COMPLETE flag set respectively
for each channel visit during scan.

The known deviation from this is rule for last
scan chan info and first (next) scan chan info
both have COMPLETE flag set. This was either
programmed with the intent of providing BSS cycle
count info or this is an artefact of firmware scan
state machine. Either way this is useless due to
short wraparound time, wraparound quirks and no
overflow notification.

Survey dumps now include only data gathered during
scan channel visits that can be computed
correctly.

This should improve hostapd ACS a little bit.

Reported-by: Srinivasa Duvvuri <sduvvuri@chromium.org>
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>