bnx2x: Prevent inner-reload while VFs exist

On some feature changes, driver employes an inner-reload flow where it
resets the function and re-configures it with the new required set of
parameters.

Such a flow proves fatal to any VF since those were not intended to be used
while HW is being reset underneath, causing them [at best] to lose all
connectivity.

This changes driver behavior to fail all configuration changes [e.g., mtu
change] requested of the driver in case VFs are active.

Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: Ariel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>