[dts] [PATCH V1] tests/TestSuite_veb_switch.py modify cores list, vf-vf switch case must contain core0

[Tu, Lijuan]

Subject format should be tests/veb_switch: xxxxxxxx

Why must contain core0, does dpdk require it?

> +        self.pmdout.start_testpmd([0,1,2,3], prefix="test1",
> + ports=[self.sriov_vfs_port[0].pci], param="--eth-peer=0,%s" %
> + self.vf1_mac)

Check firstly before use them, in case don't have enough resource.