drm/xe/pf: Enable SR-IOV VF migration

drm/xe/pf: Enable SR-IOV VF migration

All of the necessary building blocks are now in place to support SR-IOV
VF migration.
Flip the enable/disable logic to match VF code and disable the feature
only for platforms that don't meet the necessary prerequisites.
To allow more testing and experiments, on DEBUG builds any missing
prerequisites will be ignored.

Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patch.msgid.link/20251127093934.1462188-2-michal.winiarski@intel.com
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>