drm/i915: Drop WaDisableTDLUnitClockGating:vlv

WaDisableTDLUnitClockGating is only relevant for early steppings of VLV.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_pm.c

@@ -4933,7 +4933,6 @@ static void valleyview_init_clock_gating(struct drm_device *dev)
 	 * This implements the WaDisableRCZUnitClockGating:vlv workaround.
 	 */
 	I915_WRITE(GEN6_UCGCTL2,
-		   GEN7_TDLUNIT_CLOCK_GATE_DISABLE |
 		   GEN6_RCZUNIT_CLOCK_GATE_DISABLE);
 
 	/* WaDisableL3Bank2xClockGate:vlv */