drm/xe/vf: Custom GuC reset

The VF drivers can't trigger real GuC firmware reset using GDRST
register, but for the VF drivers it is sufficient to send VF_RESET
message to reset any VF specific state maintained by the GuC.
Use our existing VF bootstrap function as VF_RESET is part of it.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240604212231.1416-4-michal.wajdeczko@intel.com