[SCSI] ibmvfc: Fix terminate_rport_io

The ibmvfc driver was incorrectly obtaining a scsi_target pointer
from an fc_rport. The way it is coded ensures that ibmvfc's
terminate_rport_io handler does absolutely nothing. Fix this up
to iterate through affected devices differently, sending cancel
and abort task set as appropriate. Without this patch,
fast_io_fail_tmo is broken for ibmvfc.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>