ARM: ep93xx: Add lm70 HWMON sensor to TS-72xx boards

Register the TI TMP122 (lm70) temperature sensor driver for the TS-72xx
boards.

Originaly from Florian Fainelli. Updated to the new spi-ep93xx chip select
method.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>