drm/xe/pf: Allow to trigger VF GuC state restore from debugfs

drm/xe/pf: Allow to trigger VF GuC state restore from debugfs

For feature enabling and testing purposes, allow to restore saved
or replaced VF GuC state from debugfs, bypassing normal migration
flow. This is available only under strict debug config.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Tomasz Lis <tomasz.lis@intel.com>
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240912203817.1880-7-michal.wajdeczko@intel.com