drm/i915/rkl: Add RKL platform info and PCI ids

Introduce the basic platform definition, macros, and PCI IDs.

Bspec: 44501
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Caz Yokoyama <caz.yokoyama@intel.com>
Cc: Aditya Swarup <aditya.swarup@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Acked-by: Caz Yokoyama <caz.yokoyama@intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200504225227.464666-2-matthew.d.roper@intel.com