ath6kl: Expose ath6kl's WOW capabilities to cfg80211

Set the list of ath6kl's WOW trigger options in wiphy->wowlan.flags
variable during wiphy registration. So that, those options can be
configured via iw.

Signed-off-by: Raja Mani <rmani@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>