V4L/DVB (9583): Remember chip id of devices at initialization

When setting up the device, remember the chip id, so we can control behavior
in the future without having to read the register continuously.

Signed-off-by: Devin Heitmueller <devin.heitmueller@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>