Up to Coffeelake we could deduce this GT number from the device ID.
This doesn't seem to be the case anymore. This change reorders pciids
per GT and adds a gt field to intel_device_info. We set this field on
the following platforms :

   - SNB/IVB/HSW/BDW/SKL/KBL/CFL/CNL

Before & After :

$ modinfo drivers/gpu/drm/i915/i915.ko | grep ^alias | wc -l
209

v2: Add SNB & IVB (Chris)

v3: Fix compilation error in early-quirks (Lionel)

v4: Fix inconsistency between FEATURE/PLATFORM macros (Ville)
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20170830161208.29221-2-lionel.g.landwerlin@intel.com