hwmon: Add driver for Texas Instruments TMP512/513 sensor chips.

TI's TMP512/513 are I2C/SMBus system monitor chips. These chips
monitor the supply voltage, supply current, power consumption
and provide one local and up to three (TMP513) remote temperature sensors.

It has been tested using a TI TMP513 development kit (TMP513EVM)

Signed-off-by: Eric Tremblay <etremblay@distech-controls.com>
Link: https://lore.kernel.org/r/20191112223001.20844-3-etremblay@distech-controls.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>