drm/xe/vf: Don't try to capture engine data unavailable to VF

Don't capture engine ring registers as thoe are not available for
the VF driver.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240213154355.1221-3-michal.wajdeczko@intel.com