hwmon: (applesmc) Add support for Mac Pro 2 x Quad-Core

At least the 2x Quad-Core Apple Mac Pro appears to have some over-heat
protection which suddenly powers off the whole box under load.  This adds
support for the fans and temerature sensors in the Mac Pro - later some
"windwarm" a-like code should probably monitor the values.  For now
manually tweaking the fans prevents the sudden shutdown for me.

cd /sys/devices/platform/applesmc.768
for x in fan{1,2,3,4}; do
	echo 1 > ${x}_manual
	echo 1285 > ${x}_output
done

Two sensors are 0, while four are 129 °C, those might be removed again,
later.

Signed-off-by: René Rebe <rene@exactcode.de>
Cc: Nicolas Boichat <nicolas@boichat.ch>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>