isci: remove port start handler

isci: remove port start handler

remove the handler from the port state handler table and implement the
logic directly in scic_sds_port_start().

Signed-off-by: Piotr Sawicki <piotr.sawicki@intel.com>
[remove a level of indirection]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>