net/mlx5: fix master device Netlink socket sharing

net/mlx5: fix master device Netlink socket sharing

There is the patch [1] that uses master device Netlink socket
to retrieve master device link settings. This is not thread safe
because this resource may be in use by other call to the master
device itself. Using the same Netlink socket concurrently from
the multiple threads causes Netlink requests malfunction and
must be eliminated. The patch replaces master Netlink socket
with the socket from representor device.

[1] http://patches.dpdk.org/patch/53120/

Fixes: 0333b2f584d9 ("net/mlx5: inherit master link settings for representors")
Cc: stable@dpdk.org
Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Acked-by: Shahaf Shuler <shahafs@mellanox.com>