Added a Kconfig option to enable SOC_DCDC_NRF52X_HV for nice_nano_v2
and mikoto. According to Nordic's documentation, the DC/DC regulator is
more efficient than the LDO regulator, so this is enabled by default.
The following boards do not support this mode and were not changed:
- nice_nano
- nice60
- nrfmicro_11, nrfmicro_13
- nrf52840_m2
- bluemicro840
I could not find schematics to confirm whether the following boards
support this mode:
- bt60_v1, bt60_v2
- bt65_v1
- bt75_v1
- corneish_zen_v1, corneish_zen_v2
- pillbug
- puchi_ble_v1
- s40nc
