[SCSI] HP XP devinfo update

According to Anthony Cheung all HP XP arrays with "OPEN-" 
types support REPORT_LUN. So there is no reason why we
shouldn't use it.

Signed-off-by: Anthony Cheung <anthony.cheung@hp.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>