drm/xe: Introduce xe_ggtt_largest_hole

Introduce a new xe_ggtt_largest_hole helper that attends the SRIOV
demand and continue with the goal of limiting drm_mm access to xe_ggtt.

v2: Fix a typo (Michal)

Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240821193842.352557-8-rodrigo.vivi@intel.com


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