drm/i915/xe2lpd: display capability register definitions

Register definitions to track the reported scalable display
feature configurations

Bspec: 71161
Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231001113155.80659-2-vinod.govindapillai@intel.com


Signed-off-by: Jouni Högander <jouni.hogander@intel.com>