drm/xe/pf: Invalidate LMTT during LMEM unprovisioning

Invalidate LMTT immediately after removing VF's LMTT page tables
and clearing root PTE in the LMTT PD to avoid any invalid access
by the hardware (and VF) due to stale data.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Piotr Piórkowski <piotr.piorkowski@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20250711193316.1920-6-michal.wajdeczko@intel.com