hwmon: End of I/O region off-by-one

Fix an off-by-one error in the I/O region declaration of two
hardware monitoring drivers (lm78 and w83781d.) We were requesting
one extra port at the end of the region.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>