isci: unify port reset, add_phy, and remove_phy handlers

Unify the implementations and remove the state handlers.

Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Piotr Sawicki <piotr.sawicki@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>