ath11k: FILS discovery and unsolicited broadcast probe response support

This patch adds driver support for FILS discovery and unsolicited
broadcast probe response transmission features which are used for
in-band discovery in 6GHz band.
Currently this support is enabled only in 6GHz by setting hardware flags.

Changes include WMI commands to enable transmission, set packet
interval, set template, and handle events.

Signed-off-by: Aloka Dixit <alokad@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20201007204036.19780-1-alokad@codeaurora.org