qtnfmac: generate local disconnect event in disconnect callback

When cfg80211 disconnect callback is triggered and command is
processed by firmware, disconnect event with local parameter
set must be sent immediately. Indicating that it's a "local"
event (not from AP) will help upper layers to process this
event correctly.

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