rtl8xxxu: Fix OOPS if user tries to add device via /sys

This driver relies on driver_info in struct usb_device_id, so allowing
adding a device via /sys/bus/usb/drivers/rtl8xxxu/new_id will cause a
NULL pointer dereference.

Set .no_dynamic_id = 1 to disable hot add of USB IDs.

Reported-by: Xose Vazquez Perez <xose.vazquez@gmail.com>
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>