power: supply: cros_usbpd: reclassify "default case!" as debug

power: supply: cros_usbpd: reclassify "default case!" as debug

This doesn't need to be printed every second as an error:
...
<3>[17438.628385] cros-usbpd-charger cros-usbpd-charger.3.auto: Port 1: default case!
<3>[17439.634176] cros-usbpd-charger cros-usbpd-charger.3.auto: Port 1: default case!
<3>[17440.640298] cros-usbpd-charger cros-usbpd-charger.3.auto: Port 1: default case!
...

Reduce priority from ERROR to DEBUG.

Signed-off-by: Grant Grundler <grundler@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>