thermal/drivers/armada: Simplify name sanitization

Simplify the code by using the helper we have for doing exactly this.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20240320104940.65031-1-linux@rasmusvillemoes.dk