drm/i915/ehl: Add EHL platform info and PCI IDs

Add known EHL PCI IDs.

v2 (Rodrigo): Removed x86 early quirk. To be sent in a separated
   	      patch cc'ing the appropriated list and maintainers for
	      proper ack.
v3: (Rodrigo): - Removed .num_pipes = 3 that is coming since GEN&_FEATURES.
    	       - Added ppgtt type and size after rework from Bob and Chris
v4: (Rodrigo): - remove ppgtt type added on v3. Jose pointed it is not
    	       	 needed.

Cc: Bob Paauwe <bob.j.paauwe@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: James Ausmus <james.ausmus@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Bob Paauwe <bob.j.paauwe@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190322175847.25707-1-rodrigo.vivi@intel.com