->prereset() returns -ENOENT to tell libata that the port is empty and
reset sequencing should be stopped.  This is not an error condition.
Update ata_eh_reset() such that it sets device classes to ATA_DEV_NONE
and return success in on -ENOENT.  This makes spurious error message
go away.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
                rc = prereset(ap);
                if (rc) {
                        if (rc == -ENOENT) {
-                               ata_port_printk(ap, KERN_DEBUG, "port disabled. ignoring.\n");
+                               ata_port_printk(ap, KERN_DEBUG,
+                                               "port disabled. ignoring.\n");
                                ap->eh_context.i.action &= ~ATA_EH_RESET_MASK;
+
+                               for (i = 0; i < ATA_MAX_DEVICES; i++)
+                                       classes[i] = ATA_DEV_NONE;
+
+                               rc = 0;
                        } else
                                ata_port_printk(ap, KERN_ERR,
                                        "prereset failed (errno=%d)\n", rc);