qtnfmac: do not cancel scan in disconnect callback

qtnfmac: do not cancel scan in disconnect callback

Do not cancel scan in disconnect callback. If there is an active scan,
it will be cancelled by firmware, then host driver will be properly
notified by event.

Cancelling scan in disconnect callback occasionally may lead to the
following race issue. Host is able to queue one scan after scan
abort in disconnect callback, and another scan after scan abort
in event handler. As a result, firmware receives second scan
before the first scan completes.

Signed-off-by: Igor Mitsyanko <igor.mitsyanko.os@quantenna.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>