iwlwifi: fix spelling mistake "registrating" -> "registering"

Trivial fix to spelling mistake in IWL_ERR error message
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/dvm/main.c

@@ -1054,7 +1054,7 @@ static void iwl_bg_restart(struct work_struct *data)
 			ieee80211_restart_hw(priv->hw);
 		else
 			IWL_ERR(priv,
-				"Cannot request restart before registrating with mac80211\n");
+				"Cannot request restart before registering with mac80211\n");
 	} else {
 		WARN_ON(1);
 	}