[PATCH] I2C: add new atxp1 driver

Adds support for the Attansic ATXP1 I2C device, found on some x86
plattforms to change CPU and other voltages.  Depends on the previous
i2c-vid.h patch.

Signed-off-by: Sebastian Witt <se.witt@gmx.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>