asus-wmi: fix hwmon/pwm1

The code was completly broken, and should never had been sent
to the kernel. That's what happens when you write code without
hardware to test it.

Cc: stable@kernel.org
Signed-off-by: Corentin Chary <corentin.chary@gmail.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>