scsi: ibmvscsi: Wire up host_reset() in the driver's scsi_host_template

Wire up the host_reset function in our driver_template to allow a user
requested adpater reset via the host_reset sysfs attribute.

Example:

echo "adapter" > /sys/class/scsi_host/host0/host_reset

Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>