mwifiex: avoid querying wakeup reason when wowlan is disabled

In cfg80211 resume handler, we query wakeup reason from firmware and
report to cfg80211. if wowlan is disabled, connection is already
terminated during suspend. We don't need to query wakeup reason in this
case.

Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>