drm/xe/pf: Use GuC Buffer Cache during policy provisioning

Start using GuC buffer cache for the SRIOV policy configuration
actions. This is a required step before we could declare SRIOV
PF as being a reclaim safe.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250124185247.676-1-michal.wajdeczko@intel.com