drivers/tty/amiserial.c: add missing tty_unlock

commit d3a7b83f upstream.

tty_unlock is used on all other exits from the function.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/tty/amiserial.c

@@ -1113,8 +1113,10 @@ static int set_serial_info(struct async_struct * info,
 		    (new_serial.close_delay != state->close_delay) ||
 		    (new_serial.xmit_fifo_size != state->xmit_fifo_size) ||
 		    ((new_serial.flags & ~ASYNC_USR_MASK) !=
-		     (state->flags & ~ASYNC_USR_MASK)))
+		     (state->flags & ~ASYNC_USR_MASK))) {
+			tty_unlock();
 			return -EPERM;
+		}
 		state->flags = ((state->flags & ~ASYNC_USR_MASK) |
 			       (new_serial.flags & ASYNC_USR_MASK));
 		info->flags = ((info->flags & ~ASYNC_USR_MASK) |