hwmon: (w83781d) Use new style driver binding

This patch modifies the w83781d driver to use new style driver binding.
Substantial code modifications are required to deal with the new
interface, especially legacy device detection.

[JD: largely edited to make the patch smaller and to get the driver
to work again on ISA devices.]
Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>