drivers: clock_control: nrf_auxpll: add initial driver

Add a new driver for the AUXPLL peripheral found in some new Nordic
SoCs, e.g. nRF54H20. AUXPLL is used to clock some peripherals like e.g.
CAN. Note that driver is implemented natively as Nordic HAL lacks
definitions for the AUXPLL IP, this may be changed once these become
available.

Note that usage of nrf_auxpll_config_set generates unnecessary extra
assembly code compared to the proposed API in
https://github.com/zephyrproject-rtos/hal_nordic/pull/185 which
guarantees static initialization and single write access, possible in
the Zephyr context. However, current solution has been enforced until
further discussion on raw access APIs takes place.

Signed-off-by: Gerard Marull-Paretas <gerard@teslabs.com>