iwlwifi: mvm: add iwl_mvm_sta_from_mac80211

This is just a helper function to go from the mac80211
station struct to our internal one, to later allow us
to avoid temporary 'mvmsta' variables.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
index f8bf15c..6b3273d 100644
--- a/drivers/net/wireless/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
@@ -1091,7 +1091,7 @@
 				   struct ieee80211_sta *sta)
 {
 	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
-	struct iwl_mvm_sta *mvmsta = (void *)sta->drv_priv;
+	struct iwl_mvm_sta *mvmsta = iwl_mvm_sta_from_mac80211(sta);
 
 	switch (cmd) {
 	case STA_NOTIFY_SLEEP: