staging: wilc1000: removes duplicate del_timer_sync

This patch removes del_timer_sync(&periodic_rssi) which was
already performed this action.
Signed-off-by: Leo Kim <leo.kim@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wilc1000/host_interface.c

@@ -3498,7 +3498,6 @@ int wilc_deinit(struct wilc_vif *vif)
 	memset(&msg, 0, sizeof(struct host_if_msg));
 
 	if (clients_count == 1)	{
-		del_timer_sync(&periodic_rssi);
 		msg.id = HOST_IF_MSG_EXIT;
 		msg.vif = vif;