tty: sysfs: Add nbcon support for 'active'

Allow the 'active' attribute to list nbcon consoles.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240904120536.115780-15-john.ogness@linutronix.deSigned-off-by: Petr Mladek <pmladek@suse.com>

drivers/tty/tty_io.c

@@ -3567,7 +3567,7 @@ static ssize_t show_cons_active(struct device *dev,
 	for_each_console(c) {
 		if (!c->device)
 			continue;
-		if (!c->write)
+		if (!(c->flags & CON_NBCON) && !c->write)
 			continue;
 		if ((c->flags & CON_ENABLED) == 0)
 			continue;