drm/i915/icl: Remove Wa_1604302699

It seems that the documentation does not reference this any more, plus,
bit 28 does not stick when written to the register.

Therefore I can only assume this is something which was documented in the
past but got removed from the hardware in the meantime.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181129134630.8222-1-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/intel_workarounds.c

@@ -882,11 +882,6 @@ static void icl_gt_workarounds_apply(struct drm_i915_private *dev_priv)
 		   I915_READ(SUBSLICE_UNIT_LEVEL_CLKGATE) |
 		   GWUNIT_CLKGATE_DIS);
 
-	/* Wa_1604302699:icl */
-	I915_WRITE(GEN10_L3_CHICKEN_MODE_REGISTER,
-		   I915_READ(GEN10_L3_CHICKEN_MODE_REGISTER) |
-		   GEN11_I2M_WRITE_DISABLE);
-
 	/* Wa_1406838659:icl (pre-prod) */
 	if (IS_ICL_REVID(dev_priv, ICL_REVID_A0, ICL_REVID_B0))
 		I915_WRITE(INF_UNIT_LEVEL_CLKGATE,