[media] tw68: Move PCI vendor and device IDs to pci_ids.h

This commits moves the Intersil/Techwell PCI vendor ID, and
the device IDs for the TW68 PCI video capture cards.

This will allow to support future Intersil/Techwell devices
without duplicating the IDs.

Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>