lm-sensors: update homepage link

The lm-sensors.org website is down, and won't be coming back anytime soon. Use
the suggested[1], far from adequate, alternative.

[1] https://github.com/groeck/lm-sensors/issues/3



Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>