iio: adc: ad7173: move fwnode_irq_get_byname() call site

iio: adc: ad7173: move fwnode_irq_get_byname() call site

Move the call to fwnode_irq_get_byname() from the driver-specific
ad7173_fw_parse_device_config() to the shared ad_sd_init() function.

The main reason for this is that we want struct ad_sigma_delta_info to
be static const data that describes the actual ADC chip, not the
application-specific configuration or any runtime state.

Previously, this struct was being used to pass the IRQ number to the
shared ad_sd_init() function. Now, this is replaced by a boolean flag
that is set at compile time and the ad_sd_init() function handles
looking up the IRQ number instead. This also has the added benefit that
if any other drivers need to make use of this in the future, they just
have to set the flag and the shared code will take care of the rest
rather than duplicating the code in each driver.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250113-iio-adc-ad7313-fix-non-const-info-struct-v4-1-b63be3ecac4a@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>