drm/i915/selftests: Do not try to sanitize mock HW

If we are mocking the device, skip trying to sanitize the pm HW state.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190927210646.29664-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gt/intel_gt_pm.c

@@ -137,6 +137,7 @@ void intel_gt_sanitize(struct intel_gt *gt, bool force)
 
 void intel_gt_pm_disable(struct intel_gt *gt)
 {
+	if (!is_mock_gt(gt))
 		intel_sanitize_gt_powersave(gt->i915);
 }