isci: remove base_remote_device abstraction

Merge struct sci_base_remote_device into scic_sds_remote_device.  As for
now sci_base_remote_device was accessed indirectly using
scic_sds_remote_device->parent field.  Both machine state handlers are
also merged together.

Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Maciej Trela <Maciej.Trela@intel.com>
Signed-off-by: Maciej Patelczyk <maciej.patelczyk@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>