ARM: dts: sun4i-a10: fix cpu_alert temperature

When running dtbs_check thermal_zone warn about the
temperature declared.

thermal-zones: cpu-thermal:trips:cpu-alert0:temperature:0:0: 850000 is greater than the maximum of 200000

It's indeed wrong the real value is 85°C and not 850°C.

Signed-off-by: Clément Péron <peron.clem@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20201003100332.431178-1-peron.clem@gmail.com