iio: temperature: ltc2983: make use of spi_get_device_match_data()

Use spi_get_device_match_data() as it simplifies the code. No functional
change intended...

Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240222-ltc2983-misc-improv-v1-1-cf7d4457e98c@analog.com


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