ipwireless: remove unused ipw_tty::closing

It's only set, but never read because commit 01261cb943 ("tty:
ipwireless: Remove tty->closing abort from ipw_open()") removed last use
of tty::closing.

Cc: Jiri Kosina <jikos@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210610090307.2689-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/ipwireless/tty.c

@@ -54,7 +54,6 @@ struct ipw_tty {
 	unsigned int control_lines;
 	struct mutex ipw_tty_mutex;
 	int tx_bytes_queued;
-	int closing;
 };
 
 static struct ipw_tty *ttys[IPWIRELESS_PCMCIA_MINORS];
@@ -525,7 +524,6 @@ void ipwireless_tty_free(struct ipw_tty *tty)
 				printk(KERN_INFO IPWIRELESS_PCCARD_NAME
 				       ": deregistering %s device ttyIPWp%d\n",
 				       tty_type_name(ttyj->tty_type), j);
-			ttyj->closing = 1;
 			if (ttyj->port.tty != NULL) {
 				mutex_unlock(&ttyj->ipw_tty_mutex);
 				tty_vhangup(ttyj->port.tty);