drm/i915: Apply Wa_1406680159:icl,ehl as an engine workaround

The register this workaround updates is a render engine register in the
MCR range, so we should initialize this in rcs_engine_wa_init() rather
than gt_wa_init().

Closes: https://gitlab.freedesktop.org/drm/intel/issues/1222
Fixes: 36204d8 ("drm/i915/icl: Wa_1406680159")
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200311162300.1838847-6-matthew.d.roper@intel.com
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>

drivers/gpu/drm/i915/gt/intel_workarounds.c

@@ -920,11 +920,6 @@ icl_gt_workarounds_init(struct drm_i915_private *i915, struct i915_wa_list *wal)
 			    SLICE_UNIT_LEVEL_CLKGATE,
 			    MSCUNIT_CLKGATE_DIS);
 
-	/* Wa_1406680159:icl */
-	wa_write_or(wal,
-		    SUBSLICE_UNIT_LEVEL_CLKGATE,
-		    GWUNIT_CLKGATE_DIS);
-
 	/* Wa_1406838659:icl (pre-prod) */
 	if (IS_ICL_REVID(i915, ICL_REVID_A0, ICL_REVID_B0))
 		wa_write_or(wal,
@@ -1487,6 +1482,11 @@ rcs_engine_wa_init(struct intel_engine_cs *engine, struct i915_wa_list *wal)
 		/* Wa_1407352427:icl,ehl */
 		wa_write_or(wal, UNSLICE_UNIT_LEVEL_CLKGATE2,
 			    PSDUNIT_CLKGATE_DIS);
+
+		/* Wa_1406680159:icl,ehl */
+		wa_write_or(wal,
+			    SUBSLICE_UNIT_LEVEL_CLKGATE,
+			    GWUNIT_CLKGATE_DIS);
 	}
 
 	if (IS_GEN_RANGE(i915, 9, 12)) {