drm/xe: Set PTE_DM bit for stolen on MTL

Integrated graphics 1270 and beyond should set the PTE_LM bit in the PTE
when it's stolen memory. Add a new function, xe_bo_is_stolen_devmem(),
and use it when encoding the PTE.

In some places in the spec the PTE bit is called "Local Memory",
abbreviated as LM, and in others it's called "Device Memory" (DM). Since
we moved away from "Local Memory" and preferred the "vram" terminology,
also rename the macros as DM to follow the name of the new function.

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://lore.kernel.org/r/20230726160708.3967790-7-lucas.demarchi@intel.com


Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>