[SCSI] bnx2fc: Support interface creation on non-VLAN interface also.

bnx2fc had an assumption that the fcoe interface will always start on the vlan
dev. However, some switch implementations (Eg., HP virtual connect FlexFabric)
expects the fcoe interface to be started on physical interface. Do not error
out if the netdev is not a vlan dev.

Signed-off-by: Bhanu Prakash Gollapudi <bprakash@broadcom.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>