net/mlx5: E-Switch, Fix error flow memory leak

Fix memory leak in case query nic vport command failed.

Fixes: 81848731

 ('net/mlx5: E-Switch, Add SR-IOV (FDB) support')
Signed-off-by: Mohamad Haj Yahia <mohamad@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>