ata: libata-scsi: Cleanup ata_get_xlat_func()

Remove the unnecessary "break" after the return statement in the
MODE_SELECT/MODE_SELECT_10 case.

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