iwlwifi: mvm: rely on mac80211 to configure TWT support

Mac80211 will check both the HE Capability IE and the
Extended Capability IE, so set the TWT support bit when
mac80211 tells us to.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>