sample.bluetooth.peripheral_hr build fails on rv32m1_vega_ri5cy

[pabigot]

Recording this as an official issue since it's starting to show up in PR builds:

samples/bluetooth/peripheral_hr/sample.bluetooth.peripheral_hr_rv32m1_vega_ri5cy in rv32m1_vega_ri5cy:samples/bluetooth/peripheral_hr/sample.bluetooth fails CI as demonstrated at the first failure of https://buildkite.com/zephyr/zephyr-daily/builds/190.

/workdir/zephyr/subsys/bluetooth/controller/hci/hci.c:32:10: fatal error: lll_sync_iso.h: No such file or directory
   32 | #include "lll_sync_iso.h"
      |          ^~~~~~~~~~~~~~~~

This will be fixed by #31005 when that gets merged.