Ok, I’ve pushed the investigation forward. time_daemon and TimeService.apk are included in the build, as well as calling time_daemon restore on the init.qcom.rc (boot process). So, why are they not working?
I took a look at the system apps list and, surprise, TimeService (com.qualcomm.timeservice) is not installed. WTF! But it is on the system! Check it, /system/app/TimeService/TimeService.apk!
So I tried to debug by installing it manually. I opened Termux, and ran:
$ su
# pm install /system/app/TimeService/TimeService.apk
pkg: /system/app/TimeService/TimeService.apk
Failure [INSTALL_FAILED_SHARED_USER_INCOMPATIBLE]
¡Ahá! There’s the problem. A permission/signing key issue. But I cannot investigate further because, as you now, closed source code is not reviewable (I can’t see what the AndroidManifest.xml says, 
). All this Qcom time thingies are part of the FP2 blobs.
PD: there’s useful Android permissions information at /data/system/packages.xml, FYI. Time info seems to be saved on a binary file at /data/time/ats_13