[PATCH] w83627ehf: Add voltage inputs support

Add the voltage measuring support to W83627EHF. The code is based
on the patch provided by Yuan Mu from Winbond.

Signed-off-by: Yuan Mu <Ymu@winbond.com.tw>
Signed-off-by: Rudolf Marek <r.marek@sh.cvut.cz>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>