hwmon: (lm90) Update datasheet links

Update the links to the datasheet of some of the devices supported by
the lm90 driver. Also remove the links from the driver itself, so that
we don't have to update them twice each time they change.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Martyn Welch <martyn.welch@gefanuc.com>