lpfc: Fix host reset escalation killing all IOs.

Fix host reset escalation killing all IOs.

SLI-3 adapters will use a new host template. The template differs
from SLI-4 adapters in that it does not have an eh_host_reset_handler.

Lpfc has traditionally never had a host_reset. The host reset
handler was added when we ran into a stuck hardware condition on a
SLI-4 adapter. The host_reset will reset and reinit the pci function,
clearing the hardware condition.

Unfortunately, the host reset handler uses attach/detach code paths,
which makes scsi_add_host() and scsi_remove_host() calls. Meaning, a
host_reset will completely remove the scsi_host from the system. As a
new call to scsi_add_host() is made, the shost# changes, which results
in completely new scsi_devices and device names. All the older scsi
devices on the old shost# are now orphaned and unrecoverable.

We realize we need to re-implement the host_reset_handler so the scsi_host
stays registered across the host_reset, but that will be a rather
lengthy effort. In the short term, we had an immediate need to restore
the SLI-3 devices to their working behavior, with the easiest path being
to remove their host_reset handler.

Signed-off-by: Dick Kennedy <dick.kennedy@emulex.com>
Signed-off-by: James Smart <james.smart@emulex.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>