drm/i915/bdw: Add WaHdcDisableFetchWhenMasked

We already have it for chv, but was missing for bdw.

Signed-off-by: Michel Thierry <michel.thierry@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.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 79b4ca5..f521015 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -766,9 +766,11 @@
 	 * workaround for for a possible hang in the unlikely event a TLB
 	 * invalidation occurs during a PSD flush.
 	 */
+	/* WaHdcDisableFetchWhenMasked:bdw */
 	/* WaDisableFenceDestinationToSLM:bdw (GT3 pre-production) */
 	WA_SET_BIT_MASKED(HDC_CHICKEN0,
 			  HDC_FORCE_NON_COHERENT |
+			  HDC_DONOT_FETCH_MEM_WHEN_MASKED |
 			  (IS_BDW_GT3(dev) ? HDC_FENCE_DEST_SLM_DISABLE : 0));
 
 	/* Wa4x4STCOptimizationDisable:bdw */