The caching at the initial read is a bit fragile in case, say, a further
refactoring starts reading the frequencies at a time where it's not
possible. Add a note about it.
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://lore.kernel.org/r/20250917135200.1932903-1-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>