drm/i915/bdw: Remove BDW preproduction W/As until C stepping.

Let's clean this a bit

v2: Rebase after other Mika's patch that removed some BDW production workarounds.
v3: Removed stepping info.

Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 7c0c28c..5ebe46a 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -712,13 +712,12 @@
 		return ret;
 
 	/* WaDisablePartialInstShootdown:bdw */
-	/* WaDisableThreadStallDopClockGating:bdw */
-	/* FIXME: Unclear whether we really need this on production bdw. */
+	/* WaDisableThreadStallDopClockGating:bdw (pre-production) */
 	intel_ring_emit_wa(ring, GEN8_ROW_CHICKEN,
 			   _MASKED_BIT_ENABLE(PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE
 					     | STALL_DOP_GATING_DISABLE));
 
-	/* WaDisableDopClockGating:bdw May not be needed for production */
+	/* WaDisableDopClockGating:bdw */
 	intel_ring_emit_wa(ring, GEN7_ROW_CHICKEN2,
 			   _MASKED_BIT_ENABLE(DOP_CLOCK_GATING_DISABLE));