[dts] [PATCH V1] test_plans/cvl_switch_filter_test_plan.rst: add PPPOE cases and modify the format

[Tu, Lijuan]

> Subject: [dts] [PATCH V1] test_plans/cvl_switch_filter_test_plan.rst: add PPPOE
> cases and modify the format
> 
> test_plans/cvl_switch_filter_test_plan.rst: add PPPOE cases and
> modify the format.
> 
> Signed-off-by: Nannan Lu <nannan.lu at intel.com>

Applied