thermal: rcar: Make error and remove paths symmetrical with init

Swap interrupt disable and thermal zone unregistration in the error and
remove paths, to make them more symmetrical with the initialization
path.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>