DRI2: Add another Coffeelake PCI ID

A user of Adélie Linux reported that modesetting wasn't working properly on
their Intel i7-9700K-integrated UHD 630 GPU.  Xorg.0.log showed:

[   131.902] (EE) modeset(0): [DRI2] No driver mapping found for PCI device 0x8086 / 0x3e98
[   131.902] (EE) modeset(0): Failed to initialize the DRI2 extension.

Indeed, that PCI ID is missing from i965_pci_ids.  Adding it fixed the issue
and allowed the system to work with i965_dri under modesetting.