drm/i915: break TGL pci-ids in GT 1 & 2

I'll need this in IGT to identify the different kind of GTs and apply
the right performance query configuration.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200828133125.157171-1-lionel.g.landwerlin@intel.com