isci: unify port data structures

Make scic_sds_port a member of isci_port and merge their lifetimes which
means removing the port table from scic_sds_controller in favor of the
one at the isci_host level.  Merge ihost->sas_ports into ihost->ports.
_
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>