[SCSI] Revert "qla2xxx: Ramp down queue depth for attached SCSI devices when driver resources are low."

This reverts commit 3c290d0bSigned-off-by: NChad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: NSaurav Kashyap <saurav.kashyap@qlogic.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>