hwmon: (w83793d) remove redundant assignment to variable res

The variable res is being initialized with a value that
is never read and is being re-assigned a little later on. The
assignment is redundant and hence can be removed.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20191011170215.11539-1-colin.king@canonical.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>