ata_link_online — test whether the given link is online
| bool ata_link_online ( | struct ata_link * link ); | 
   Test whether link is online.  This is identical to
   ata_phys_link_online when there's no slave link.  When
   there's a slave link, this function should only be called on
   the master link and will return true if any of M/S links is
   online.