[SCSI] qla4xxx: fix scsi command completion, lun reset and target reset code

This patch contains the following:

1. when hba completion status is good, check for iscsi transport
   errors (underflow/overflow) prior to checking the scsi status

2. New firmware requires that one marker iocb be issued for each task
   management command. The patch issues marker iocb immediately
   following a LUN or Target reset.

Signed-off-by: David C Somayajulu <david.somayajulu@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>