hwmon: (lm70) Add support for TI TMP122/124

Add support for Texas Instruments TMP122/124 which are nearly identical to
their TMP121/123 except that they also support programmable temperature
thresholds.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>