Introduce ADC keys driver for input subsystem
该 MR 从主线 backport 了 ADC keys input driver，并为多模态开发套件和 CSK6012 语音开发套件增加了相关 sample 的 overlay。
-- 已打开串口 /dev/cu.usbmodem124201，波特率 115200 --
-- 按 Ctrl + C 退出 --
*** Booting Zephyr OS build zephyr-v3.4.0-50-g72d38e2eb481 ***
*** ListenAI CSK SDK Version: 2.0.0.0-92d7a8039a ***
Input sample started
input event: dev=adc-keys SYN type= 1 code= 2 value=1
input event: dev=adc-keys SYN type= 1 code= 2 value=0
input event: dev=adc-keys SYN type= 1 code= 3 value=1
input event: dev=adc-keys SYN type= 1 code= 3 value=0
input event: dev=gpio-keys SYN type= 1 code= 48 value=1
input event: dev=gpio-keys SYN type= 1 code= 48 value=0
input event: dev=gpio-keys SYN type= 1 code= 4 value=1
input event: dev=gpio-keys SYN type= 1 code= 4 value=0