net/mlx4: remove dependency on libmnl in meson
net/mlx4: remove dependency on libmnl in meson

There is no dependency on this library for mlx4.

Fixes: 1dd7c7e38c19 ("net/mlx4: support meson build")
Cc: stable@dpdk.org

Signed-off-by: David Marchand <f28529695cfa9e3e1eb84e7072aa626af4abb18e@redhat.com>
Acked-by: Raslan Darawsheh <18fd192a829ab99382a9c480ddb6085edf3e8489@mellanox.com>

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