hwmon: (cros_ec) Fix access to restricted __le16

hwmon: (cros_ec) Fix access to restricted __le16

0-day complains:

drivers-hwmon-cros_ec_hwmon.c:sparse:sparse:cast-to-restricted-__le16

Fix by using a __le16 typed variable as parameter to le16_to_cpu().

Fixes: bc3e45258096 ("hwmon: add ChromeOS EC driver")
Cc: Thomas Weißschuh <linux@weissschuh.net>
Cc: Tzung-Bi Shih <tzungbi@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20240606180507.3332237-1-linux@roeck-us.net
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>