e1_input: change prototype of close hook in e1inp_driver

This patch changes `close' so we can make the e1inp_event
inside this hook.
diff --git a/src/e1_input.c b/src/e1_input.c
index d11a3ce..77a6b3c 100644
--- a/src/e1_input.c
+++ b/src/e1_input.c
@@ -429,7 +429,7 @@
 		osmo_timer_del(&link->ts->sign.tx_timer);
 
 	if (link->ts->line->driver->close)
-		link->ts->line->driver->close(link->ts);
+		link->ts->line->driver->close(link);
 
 	talloc_free(link);
 }