drivers: clock_control_nrf2_hsfll: Fix checking if DVFS is available

To check if DVFS can be used, the CONFIG_NRFS_DVFS_LOCAL_DOMAIN symbol
needs to be used, not CONFIG_NRFS_HAS_DVFS_SERVICE which only indicates
that DVFS is technically possible, not that its local domain part is
actually included in the build.

Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>