be2net: use adapter->flags to track SRIOV state

The driver so far used adapter->num_vfs value to check if SR-IOV is enabled
or not. But, the patch bec84e6b("create optimal number of queues on SR-IOV
config") changed this logic. The adapter->num_vfs value is validated and set
much before SR-IOV is enabled. So, we now use an explicit flag to track
SR-IOV enabled state.

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>