HID: sony: Use DS4 MAC address as unique identifier on USB

The DS4 MAC address is reported as a unique identified when
using Bluetooth. For USB there is no unique identifier reported
yet, so use the MAC address.

Signed-off-by: Roderick Colenbrander <roderick.colenbrander@sony.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>