drm/i915/bdw: Update relevant error state

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -1045,6 +1045,7 @@ void i915_get_extra_instdone(struct drm_device *dev, uint32_t *instdone)
 	default:
 		WARN_ONCE(1, "Unsupported platform\n");
 	case 7:
+	case 8:
 		instdone[0] = I915_READ(GEN7_INSTDONE_1);
 		instdone[1] = I915_READ(GEN7_SC_INSTDONE);
 		instdone[2] = I915_READ(GEN7_SAMPLER_INSTDONE);