be2net: don't call vid_config() when there's no vlan config

be_vid_config() is called from be_setup() to replay config cmds after
a card reset. Skip calling it when no vlans are configured.

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