drivers/hwmon/adm1021.c: support high precision ADM1023 remote sensor

The ADM1023 temperature sensor supports higher resolution for its external
sensor (sensitivity of 1/8 deg C).  This patch makes this higher
resolution available through the appropriate temperature sysfs nodes.

Curiously, this functionality was available in the 2.4 kernel driver (but
formatted in a less helpful manner).

Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Michael Abbott <michael.abbott@diamond.ac.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>