brw/scoreboard: Disable nomask workaround for Xe2+

The issue was caused by fused EU feature that is not used in Xe2+
anymore.

Reviewed-by: Francisco Jerez <currojerez@riseup.net>

src/intel/compiler/brw/brw_lower_scoreboard.cpp

@@ -861,7 +861,7 @@ namespace {
    bool
    needs_nomask_workaround(const intel_device_info *devinfo)
    {
-      return true;
+      return devinfo->ver < 20;
    }
 
    /**