drm/i915/bxt: Mark Wa4x4STCOptimizationDisable as for Broxton also.

Signed-off-by: NNick Hoath <nicholas.hoath@intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -951,7 +951,7 @@ static int gen9_init_workarounds(struct intel_engine_cs *ring)
 				  GEN9_ENABLE_YV12_BUGFIX);
 	}
 
-	/* Wa4x4STCOptimizationDisable:skl */
+	/* Wa4x4STCOptimizationDisable:skl,bxt */
 	WA_SET_BIT_MASKED(CACHE_MODE_1, GEN8_4x4_STC_OPTIMIZATION_DISABLE);
 
 	/* WaDisablePartialResolveInVc:skl */