drm/xe/uc: Fix and start using xe_uc_fw_sanitize()

Helper xe_uc_fw_sanitize() was defined but never used. First fix
it by properly exiting also from the LOAD_FAIL state, then use it
in GuC and HuC sanitize code.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240613153424.2120-1-michal.wajdeczko@intel.com