net/mlx4: USe one wrapper that returns -EPERM

When a VF issues a firmware command which is disallowed for them, the PF
rerturns -EPERM from that command wrapper. Move to use one such wrapper
instance, instead of repeating the same code on such commands.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>