USB: digi_acceleport: do sanity checking for the number of ports

The driver can be crashed with devices that expose crafted descriptors
with too few endpoints.

See: http://seclists.org/bugtraq/2016/Mar/61

Signed-off-by: Oliver Neukum <ONeukum@suse.com>
[johan: fix OOB endpoint check and add error messages ]
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
static int digi_port_remove(struct usb_serial_port *port)
{
	struct digi_port *priv;

	priv = usb_get_serial_port_data(port);
	kfree(priv);

	return 0;
}

static int digi_port_remove(struct usb_serial_port *port)
{
	struct digi_port *priv;

	priv = usb_get_serial_port_data(port);
	kfree(priv);

	return 0;
}
