iwlwifi: remove iwl_ht_params.smps_mode

This struct member is never set, so remove it.

Since this is the last thing that needs mac80211.h, also change
the includes to no longer use mac80211.h

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>