Add custom clock_control API for nRF platforms that allows requesting
clocks with specified minimal required attributes (accuracy, precision,
and frequency). Provide an implementation of this API for FLL16M, HFXO,
HSFLL, and LFCLK controllers in the nRF54H20 SoC.
Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>
Signed-off-by: Bjarki Arge Andreasen <bjarki.andreasen@nordicsemi.no>
