Revert "cx20442: tty_ldisc_ops::write_wakeup is optional"

This reverts commit 0e9ffdb2.

It will be coming in through the ASoC tree instead.

Cc: Liam Girdwood <lgirdwood@gmail.com>
Reported-by: Mark Brown <broonie@kernel.org>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: alsa-devel@alsa-project.org
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

sound/soc/codecs/cx20442.c

@@ -279,6 +279,11 @@ static void v253_receive(struct tty_struct *tty, const unsigned char *cp,
 	}
 }
 
+/* Line discipline .write_wakeup() */
+static void v253_wakeup(struct tty_struct *tty)
+{
+}
+
 struct tty_ldisc_ops v253_ops = {
 	.name = "cx20442",
 	.owner = THIS_MODULE,
@@ -286,6 +291,7 @@ struct tty_ldisc_ops v253_ops = {
 	.close = v253_close,
 	.hangup = v253_hangup,
 	.receive_buf = v253_receive,
+	.write_wakeup = v253_wakeup,
 };
 EXPORT_SYMBOL_GPL(v253_ops);