hwmon: (adt7475) Move sysfs files removal to a separate function

Move sysfs files removal to a separate function. The code is common to
the device probing error path and the standard device removal path. As
it will grow with future driver development, this avoids code
duplication.

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