[SCSI] lpfc 8.2.7 : Rework the worker thread

Rework of the worker thread to make it more efficient.
Make a finer-grain notfication of pending work so less time is
spent checking conditions. Also made other general cleanups.

Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>