drm/i915: add Haswell devices and their PCI IDs

This adds product definitions for desktop, mobile and server boards.

v2: split into a separate patch, add .has_pch_split feature.

Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>