mac80211: move SMPS mode setting after ieee80211_prep_connection

ieee80211_mgd_assoc calls ieee80211_prep_connection which
might call ieee80211_prep_channel and set smps_mode to OFF.
That will override the previous setting of smps_mode in
ieee80211_mgd_assoc and HT SMPS will be set to "disabled"
in the association request frame.

Move the setting of smps_mode in ieee80211_mgd_assoc to
after the call to ieee80211_prep_connection.

Signed-off-by: Shaul Triebitz <shaul.triebitz@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210618133832.d8e5cc4b527f.Icf3a67fffbdd8c408c0cadfe43f8f4cffdc90acb@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>