app/testpmd: fix device configure with zero queue

app/testpmd: fix device configure with zero queue

Setup number of Rx & Tx queues to 0 at rte_eth_dev_configure means
take driver's default queue number, so if during a re-configuration
previous queue number will be overwrite, this is not expected when
we configure dcb. The patch fix it by re-configure device with the
original queue number.

Fixes: 3be82f5cc5e ("ethdev: support PMD-tuned Tx/Rx parameters")
Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
Acked-by: Remy Horton <remy.horton@intel.com>