hwmon: (adt7475) Add support for the ADT7473

Add support for the ADT7473 to the adt7475 driver, and mark the
adt7473 driver for removal. The ADT7473 and ADT7475 chips are almost
the same chip and essentially compatible, so there's no point in
having separate drivers for them.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: "Mark M. Hoffman" <mhoffman@lightlink.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Jordan Crouse <jordan@cosmicpenguin.net>
Cc: "Darrick J. Wong" <djwong@us.ibm.com>