thermal/drivers/k3: Add hwmon support

Expose the thermal sensors on K3 AM654 as hwmon devices, so that
temperatures could be read using lm-sensors.

Signed-off-by: Massimiliano Minella <massimiliano.minella@gmail.com>
Link: https://lore.kernel.org/r/20220401151656.913166-1-massimiliano.minella@se.com


Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>