mlx5: fix RETA table size
mlx5: fix RETA table size

When the number of RX queues is not a power of two,
the RETA table is configured to its maximum size for
better balancing.

Testing showed that limiting its size to 256 improves performance
noticeably with little to no  impact on balancing results.

Fixes: ebb30ec64a68 ("mlx5: increase RETA table size")

Signed-off-by: Yaacov Hazan <b9b45a5a3790ec570f214ff47368ef7b63d38fb3@mellanox.com>
Acked-by: Adrien Mazarguil <9d39ea493ca46c560334f650ac5d4b5ffbcb5cf0@6wind.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk