mfd: cros_ec: Instantiate the CrOS USB PD logger driver

Add the cros-usbpd-logger driver for logging event data for the USB PD
charger available in the Embedded Controller on ChromeOS systems. The
logging feature is logically separate functionality from charge manager,
hence is instantiated as a different driver.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Guenetr Roeck <linux@roeck-us.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>