drm/i915/skl: Extend WaDisableChickenBitTSGBarrierAckForFFSliceCS

There is ambiguity in the documentation between D0 and E0.
Extend this workaround to E0.

References: BSID#779
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1465309159-30531-23-git-send-email-mika.kuoppala@intel.com

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -1085,7 +1085,7 @@ static int skl_init_workarounds(struct intel_engine_cs *engine)
 			   _MASKED_BIT_ENABLE(GEN9_FFSC_PERCTX_PREEMPT_CTRL));
 	}
 
-	if (IS_SKL_REVID(dev_priv, 0, SKL_REVID_D0)) {
+	if (IS_SKL_REVID(dev_priv, 0, SKL_REVID_E0)) {
 		/* WaDisableChickenBitTSGBarrierAckForFFSliceCS:skl */
 		I915_WRITE(FF_SLICE_CS_CHICKEN2,
 			   _MASKED_BIT_ENABLE(GEN9_TSG_BARRIER_ACK_DISABLE));