drm/i915: Record platform specific ppGTT size in intel_device_info

As the maximum addressable bits is determined by platform, record that
information in our static chipset tables. This has the advantage of
being clearly recorded in our capability dumps for dmesg, debugfs and
error states.

Based on a patch by Bob Paauwe.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Bob Paauwe <bob.j.paauwe@intel.com>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190314223839.28258-2-chris@chris-wilson.co.uk