apm821xx: WNDR4700: use upstream tc654 cooling devices

apm821xx: WNDR4700: use upstream tc654 cooling devices

Upstream hwmon-maintainer had various comments about
the changes to the tc654 driver. These have been
addressed and the cooling device support is destined
for inclusion.

One of the comments was the change of the cooling states
scaling. No longer the driver uses the same values as the
hwmon interface, instead the states are now the 17 states
the tc654 supports.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>