[SCSI] pm80xx: WWN Modification for PM8081/88/89 controllers

Individual WWN read operations based on controller.
PM8081 - Read WWN from Flash VPD.
PM8088/89 - Read WWN from EEPROM.
PM8001 - Read WWN from NVM.

Signed-off-by: Sakthivel K <Sakthivel.SaravananKamalRaju@pmcs.com>
Signed-off-by: Anand Kumar S <AnandKumar.Santhanam@pmcs.com>
Acked-by: Jack Wang <jack_wang@usish.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>