drm/xe/nvm: add on-die non-volatile memory device

Enable access to internal non-volatile memory on DGFX
with GSC/CSC devices via a child device.
The nvm child device is exposed via auxiliary bus.

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Link: https://lore.kernel.org/r/20250617145159.3803852-7-alexander.usyskin@intel.com


Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>