qtnfmac: implement basic WoWLAN support

This patch implements basic WoWLAN support in qtnfmac driver, including
processing of WoWLAN features reported by firmware and implementation
of cfg80211 suspend/resume/wakeup callbacks. Currently the following
WoWLAN triggers are supported: disconnect, magic packet,
custom pattern packet.

Signed-off-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>