iio: dac: ds4424: use device match data for chip info

iio: dac: ds4424: use device match data for chip info

Refactor the driver to use device match data instead of checking ID enums
in a switch statement.

Define a `ds4424_chip_info` structure to hold variant-specific attributes
(currently just the channel count) and attach it directly to the I2C and
OF device ID tables.

This simplifies the probe function and makes it easier to add support for
new variants like DS4402/DS4404.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>