[SCSI] qla2xxx: Handle device mapping changes due to device logout.

A device logout sent in the delete path of a fcport would clear the
port handle binding inside the firmware. This could lead to queued
work items for the fcport, if any, getting incorrect results. This
patch fixes the issue by checking for device name changes after a
call to get port database.

Signed-off-by: Arun Easi <arun.easi@qlogic.com>
Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>