drm/i915: add Ivy Bridge GT2 Server entries

This adds PCI ID for IVB GT2 server variant which we were missing.

Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
[danvet: fix up conflict because the patch has been diffed against next. tsk.]
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>