thermal: imx: use consistent style to write temperatures

The previous commit already took care to use the right notation for
temperatures. Add correct units to all values representing temperatures in
the right notation for the rest of the file.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>