isci: unify remote_device stop_handlers

Implement all states in scic_remote_device_stop() and delete the state
handlers.
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/scsi/isci/remote_device.h

@@ -386,12 +386,6 @@ typedef void (*scic_sds_remote_device_ready_not_ready_handler_t)(
  *
  */
 struct scic_sds_remote_device_state_handler {
-	/**
-	 * The stop_handler specifies the method invoked when a user attempts to
-	 * stop a remote device.
-	 */
-	scic_sds_remote_device_handler_t stop_handler;
-
 	/**
 	 * The fail_handler specifies the method invoked when a remote device
 	 * failure has occurred.  A failure may be due to an inability to