pci: add missing PCI id of Coffee Lake GPU

[corvink]

Summary

The PCI id of an UHD Graphics 630 for Coffee Lake GPUs is missing in
the PCI id list of all Intel GPUs.

You can take a look at https://dgpu-docs.intel.com/devices/hardware-table.html to check that this device id exists.
Or check the linux code: https://github.com/torvalds/linux/commit/d0e062ebb3a44b56a7e672da568334c76f763552

[corvink]

@kib @bwidawsk @imp I added you as reviewer because I saw you've added the original file.

[kib]

Is this stuff really useful? Supposedly it works around BIOS bugs, by reserving stolen memory if BIOS erronously reported it as regular memory.

But it was never properly integrated with the drm bits. And since it was not, I doubt that we need this stuff in the kernel at all.

[corvink]

I have to detect intel_graphics_stolen_base and intel_graphics_stolen_size for GPU passthrough to work properly (see D26209). Instead of duplicating the code of pci_early_quirks.c, I'm reusing these variables. Since one of my devices has this missing device id, GPU passthrough doesn't work on that device.