hwmon: VRM is not read from registers

The VRM value is not read from chip registers, so there's no need
to update the device data cache before exporting the VRM value to
user-space.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Hans de Goede <j.w.r.degoede@hhs.nl>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>