vxge: Pass correct number of VFs value to pci_sriov_enable().

-  max_config_dev loadable parameter is set to 0xFF by default. Pass correct
   number of VFs value to pci_sriov_enable() if max_config_dev is set to its 
   default value.
 
Signed-off-by: Sreenivasa Honnur <sreenivasa.honnur@exar.com>
Signed-off-by: Ramkrishna Vepa <ram.vepa@exar.com>
Signed-off-by: David S. Miller <davem@davemloft.net>