power: supply: olpc_battery: correct the temperature units

commit ed54ffbe554f0902689fd6d1712bbacbacd11376 upstream.

According to [1] and [2], the temperature values are in tenths of degree
Celsius. Exposing the Celsius value makes the battery appear on fire:

  $ upower -i /org/freedesktop/UPower/devices/battery_olpc_battery
  ...
      temperature:         236.9 degrees C

Tested on OLPC XO-1 and OLPC XO-1.75 laptops.

[1] include/linux/power_supply.h
[2] Documentation/power/power_supply_class.txt

Fixes: fb972873 ("[BATTERY] One Laptop Per Child power/battery driver")
Cc: stable@vger.kernel.org
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>