iio: proximity: aw96103: Add support for aw96103/aw96105 proximity sensor

AW96103 is a low power consumption capacitive touch and proximity controller.
Each channel can be independently config as sensor input, shield output.

Channel Information:
  aw96103: 3-channel
  aw96105: 5-channel

Signed-off-by: shuaijie wang <wangshuaijie@awinic.com>
Link: https://patch.msgid.link/20240827080229.1431784-3-wangshuaijie@awinic.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>