thermal: Fix spelling mistake "disabed" -> "disabled"

There is a spelling mistake in a comment, fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20210311093054.5338-1-colin.king@canonical.com