i965/drm: Drop intel_chipset.h in favor of using gen_device_info.

i965/drm: Drop intel_chipset.h in favor of using gen_device_info.

This moves the PCI ID detection to intel_screen.c and makes
drm_bacon_bufmgr_gem_init() take a devinfo pointer.

We also drop the HAS_LLC query stuff - devinfo has that info already,
without kernel queries, and it makes no sense to have two has_llc flags
set by different mechanisms.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Jason Ekstrand <jason@jlekstrand.net>