drm/xe/pf: Skip LMTT update if no LMEM was provisioned

During VF unprovisioning, if VF was not provisioned with LMEM,
there is no need to trigger LMTT update, as VF LMTT was never
set. This will spare us sending full TLB invalidation requests.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Link: https://lore.kernel.org/r/20250801144418.180584-1-michal.wajdeczko@intel.com