[SCSI] bnx2fc: Send solicitation only after vlan discovery is complete

Link up event is generated to the driver even before vlan discovery has
started. Because of this driver can send discovery solicitation on a stale
vlan. Call fcoe_ctlr_link_up() only when the driver is in enabled state, which
implies the vlan discovery is complete before sending solicitation.

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