ata: libata-scsi: rework ata_dump_status to avoid using pr_cont()

pr_cont() has the problem that individual calls will be disrupted
under high load, causing each call to end up on a single line and
thereby mangling the output.
So rework ata_dump_status() to have just one call to ata_port_warn()
and avoid this problem.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>