The ChromeOS Embedded Controller exposes fan speed and temperature
readings.
Expose this data through the hwmon subsystem.

The driver is designed to be probed via the cros_ec mfd device.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240529-cros_ec-hwmon-v4-2-5cdf0c5db50a@weissschuh.net
[tzungbi: Fixed typo in MAINTAINERS: "chros_ec_hwmon" -> "cros_ec_hwmon"]
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>