Instead of driver returning DID_NO_CONNECT during driver unload allow SSU
and Sync Cache commands to be sent to the controller to flush any cached
data from the drive.

Link: https://lore.kernel.org/r/20210520152545.2710479-16-kashyap.desai@broadcom.com
Cc: sathya.prakash@broadcom.com
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>