tty: ipwireless, cleanup TIOCGSERIAL

In ipwireless_get_serial_info, struct serial_struct is memset to 0 and
then some members set to 0 explicitly.

Remove the latter as it is obviously superfluous.

And remove the retinfo check against NULL. copy_to_user will take care
of that.

Part of hub6 cleanup series.

Signed-off-by: Jiri Slaby <[e-mail]>
Cc: Jiri Kosina <[e-mail]>
Acked-by: David Sterba <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/ipwireless/tty.c

···
 {
 	struct serial_struct tmp;
 
-	if (!retinfo)
-		return (-EFAULT);
-
 	memset(&tmp, 0, sizeof(tmp));
 	tmp.type = PORT_UNKNOWN;
 	tmp.line = tty->index;
-	tmp.port = 0;
-	tmp.irq = 0;
-	tmp.flags = 0;
 	tmp.baud_base = 115200;
-	tmp.close_delay = 0;
-	tmp.closing_wait = 0;
-	tmp.custom_divisor = 0;
-	tmp.hub6 = 0;
+
 	if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
 		return -EFAULT;