ti-soc-thermal: Fix a typo in a comment line

Add a missing character in this description for a function.

Acked-by: Keerthy <j-keerthy@ti.com>
Tested-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>