net/mlx5: fix descriptors number adjustment

net/mlx5: fix descriptors number adjustment

The number of descriptors to configure in a Rx/Tx queue is passed to
the mlx5_tx/rx_queue_pre_setup() function by value. That means any
adjustments of this variable are local and cannot affect the actual
value that is used to allocate mbufs in the mlx5_txq/rxq_new()
functions. Pass the number as a reference to actually update it.

Fixes: 6218063b39a6 ("net/mlx5: refactor Rx data path")
Fixes: 1d88ba171942 ("net/mlx5: refactor Tx data path")
Cc: stable@dpdk.org
Signed-off-by: Alexander Kozyrev <akozyrev@mellanox.com>
Acked-by: Matan Azrad <matan@mellanox.com>