Add board-level support for ES7210 4-ch ADC on lckfb-szpi-esp32s3:
- configs/es7210/defconfig: Board configuration with I2C0, I2S0,
ES7210 driver enabled. I2S pins: BCLK=14, DIN=12, MCLK=38, WS=13,
sample rate 48kHz.
- src/esp32s3_board_es7210.c: Board init registering ES7210 on I2C0
bus with I2S0 as audio transport
- src/esp32s3_bringup.c: Call ES7210 board init on startup; skip
generic I2S audio device registration on I2S0 when ES7210 is
enabled to avoid conflicting audio device on the same port
- src/esp32s3-szpi.h: ES7210 I2C address and device path defines
- src/Make.defs: Build integration for CONFIG_AUDIO_ES7210
Tested: 48kHz/2ch/16bit recording on ESP32-S3 (lckfb-szpi N16R8),
verified with nxrecorder and es7210_test.
Signed-off-by: wangjianyu3 <wangjianyu3@xiaomi.com>