[SCSI] allow REPORT LUN scanning even for LUN 0 PQ of 3

Currently we just ignore the device, which means there are a few
arrays out there that we don't find.

This patch updates the scsi_report_lun_scan() to take a target instead
of a device so it can be called on a return of
SCSI_SCAN_TARGET_PRESENT, which is what a PQ 3 device returns.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>