hwmon: (dell-smm) Enable broken functionality via "force" module param

Some Dell machines are broken and some functionality is disabled. Show
warning into dmesg about this fact and allow user via "force" module param
to override brokenness and enable broken functionality.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>