[SCSI] libfcoe: Use fka_period as periodic timeouts to age out fcf if

[SCSI] libfcoe: Use fka_period as periodic timeouts to age out fcf if

keep alives are disabled due to fd_flags set and also
stop updating keep alive values in that case.

Update select fcf time only if fcf is not already selected or
select time is not already determined from parse adv, and then
have select time cleared only once after fcf is selected.

Changed deadline check to time_after_eq() from time_after()
since now next timeout will be on exact 2.5 times FKA followed
by first advertisement.

Signed-off-by: Vasu Dev <vasu.dev@intel.com>
Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>