cdc_ncm: do not call usbnet_link_change from cdc_ncm_bind

usbnet_link_change will call schedule_work and should be
avoided if bind is failing. Otherwise we will end up with
scheduled work referring to a netdev which has gone away.

Instead of making the call conditional, we can just defer
it to usbnet_probe, using the driver_info flag made for
this purpose.

Fixes: 8a34b0ae8778 ("usbnet: cdc_ncm: apply usbnet_link_change")
Reported-by: Andrey Konovalov <andreyknvl@gmail.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
static ssize_t cdc_ncm_store_rx_max(struct device *d,  struct device_attribute *attr, const char *buf, size_t len)
{
	struct usbnet *dev = netdev_priv(to_net_dev(d));
	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
	unsigned long val;

	if (kstrtoul(buf, 0, &val) || cdc_ncm_check_rx_max(dev, val) != val)
		return -EINVAL;

	cdc_ncm_update_rxtx_max(dev, val, ctx->tx_max);
	return len;
}

static ssize_t cdc_ncm_store_rx_max(struct device *d,  struct device_attribute *attr, const char *buf, size_t len)
{
	struct usbnet *dev = netdev_priv(to_net_dev(d));
	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
	unsigned long val;

	if (kstrtoul(buf, 0, &val) || cdc_ncm_check_rx_max(dev, val) != val)
		return -EINVAL;

	cdc_ncm_update_rxtx_max(dev, val, ctx->tx_max);
	return len;
}
