esp_ldo_acquire_channel() function

- ESP_OK: Acquire the LDO channel successfully - ESP_ERR_INVALID_ARG: Acquire the LDO channel failed due to invalid arguments - ESP_FAIL: Acquire the LDO channel failed due to other reasons

This function can't automatically search a LDO channel for you, you must specify a LDO channel ID manually, based on your schematic. The same channel can be acquired multiple times in different places of the application code, however, if the LDO channel is adjustable, you can't acquire it multiple times, in case user A changes the voltage and breaks the voltage setting of user B. You should release the channel by `esp_ldo_release_channel` when it's no longer needed.