[PATCH] libata-eh: Remove layering violation and duplication when handling absent ports

This removes the layering violation where drivers have to fiddle
directly with EH flags. Instead we now recognize -ENOENT means "no port"
and do the handling in the core code.

This also removes an instance of a call to disable the port, and an
identical printk from each driver doing this. Even better - future rule
changes will be in one place only.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>