cam: Provide compatibility for CAMGETPASSTHRU for periph drivers

The CAM version bump 0x19 -> 0x1a changed the CAMGETPASSTHRU definition,
so applications using the old ioctl are broken. However, that version
change did not affect anything relating to the ioctl implementation for
periphs.

Fixes: 8f9be1eed11c ("cam(4): Improve XPT_DEV_MATCH")
PR: 264709
Tested by: andreas.mahling@googlemail.com
Reviewed by: imp
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D36389