hwmon: (w83781d) Fix compile warning

The following compile warning may be seen if the driver is compiled with
-Wuninitialized:

drivers/hwmon/w83781d.c: warning: 'sc_addr[1]' may be used uninitialized in this
function [-Wuninitialized]

While this is a false positive, it is annoying in nightly builds, and may help
to conceal real problems. The current code is quite tricky, and and it is easy
to rearrage the code to make the warning disappear. So fix it.

Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>