hwmon: (lm90) Restore original configuration if probe function fails

The lm90 driver restores the original chip configuration in its exit function.
However, the chip configuration is not restored if the probe function fails.
Restore it there as well.

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