systat -vmstat vs. acd

[Andriy Gapon]

With 4.X on ATA(PI)-only machine systat -vmstat used to show disks
statistics for both ad and acd devices. Now, in 5.4-RELEASE, it shows
statistics only for ad devices. If atapicam is added then statistics for
cd and pass devices is shown as well.

Is this a correct/expected behaviour ?
Is there any way to get acd statistics ?
Should I file a PR ?

-- 
Andriy Gapon