[dts] [PATCH V1] tests/cvl_advanced_iavf_rss: remove the steps after destroying rss rules

[Tu, Lijuan]

> a)according to test plan, delete the steps after destroying rss rules for toeplitz
> cases.
> b)according to test plan, remove the code of nvgre packet for
> symmetric_mac_ipv6_tcp.
> c)according to test plan, modify check point for symmetric cases which check
> different hash value after destroying rss rule.
> d)the behavior after destroying rss rules are not unified, it need to launch
> testpmd separately for each case.
> 
> Signed-off-by: Xie wei <weix.xie at intel.com>

Applied