iio: frequency: adf4371: make use of spi_get_device_match_data()

iio: frequency: adf4371: make use of spi_get_device_match_data()

To use spi_get_device_match_data(), add the chip_info structure to the
of_device_id table which is always a good thing to do.

While at it, added dedicated variables for each chip (instead of the
harder to maintain array) and added a new string variable for the part
name.

Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://patch.msgid.link/20241009-dev-adf4371-minor-improv-v1-1-97f4f22ed941@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>