mlx4: Use actual number of PCI functions (PF + VFs) for alias GUID logic

The code which is dealing with SRIOV alias GUIDs in the mlx4 IB driver has some
logic which operated according to the maximal possible active functions (PF + VFs).

After the single port VFs code integration this resulted in a flow of false-positive
warnings going to the kernel log after the PF driver started the alias GUID work.

Fix it by referring to the actual number of functions.

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