net/tap: forbid different Rx/Tx queue number

net/tap: forbid different Rx/Tx queue number

Users can create the desired number of RxQ and TxQ in DPDK. For
example, if the number of RxQ = 2 and the number of TxQ = 5,
a total of 8 file descriptors will be created for a tap device,
including RxQ, TxQ, and one for keepalive. The RxQ and TxQ
with the same ID are paired by dup(2).

In this scenario, Kernel will have 3 RxQ where packets are
incoming but not read. The reason for this is that there are only
2 RxQ that are polled by DPDK, while there are 5 queues in Kernel.
This patch add a checking if DPDK has appropriate numbers of
queues to avoid unexpected packet drop.

Signed-off-by: Nobuhiro Miki <nmiki@yahoo-corp.jp>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>