iio: adc: at91-sama5d2_adc: get rid of 5 degrees Celsius adjustment

On SAMA7G5 final chip version there is no need for 5 degrees Celsius
adjustment when computing junction temperature, thus, remove it.

Fixes: 5ab38b81 ("iio: adc: at91-sama5d2_adc: add support for temperature sensor")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20221020102705.3639204-1-claudiu.beznea@microchip.com


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