ath10k: enable spectrum management support

Indicate spectrum management support in hardware
flags, while we already handle power set
(IEEE80211_CONF_CHANGE_POWER) in the ath10k driver.
This enable 802.11h support for station mode.

Signed-off-by: Janusz Dziedzic <janusz.dziedzic@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>