be2net: implement .sriov_configure() PCI callback

This patch implements the .sriov_configure() PCI method to allow for
runtime enabling/disabling of VFs. The module param "num_vfs" is now
deprecated.
At the time of driver load the PF-pool resources are allocated to the PF.
When the user enables VFs, the resources are then re-distributed across
PFs and VFs based on the number of VFs enabled.
Signed-off-by: Vasundhara Volam <vasundhara.volam@emulex.com>

Signed-off-by: Sathya Perla <sathya.perla@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>