[SCSI] fcoe: removes fcoe_watchdog

Removes periodic fcoe_watchdog timer used across all fcoe interface
maintained in fcoe_hostlist instead added new fcoe_queue_timer
per fcoe interface.

Added timer is armed only when some pending skb need to be flushed
as oppose to periodic 1 second fcoe_watchdog, since now
fcoe_queue_timer is used on demand thus set this to 2 jiffies.

Now fcoe_queue_timer is much simple than fcoe_watchdog using lock to
process all fcoe interface from fcoe_hostlist.

I noticed +ve performance result with using 2 jiffies timer as
this helps flushing fcoe_pending_queue quickly.

Signed-off-by: Vasu Dev <vasu.dev@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>