hwmon: (w83791d) use simple i2c probe

This driver doesn't use the id information provided by the old i2c
probe function, so it can trivially be converted to the simple
("probe_new") form.

Signed-off-by: Stephen Kitt <steve@sk2.org>
Link: https://lore.kernel.org/r/20200813162026.1512242-1-steve@sk2.org


Signed-off-by: Guenter Roeck <linux@roeck-us.net>