Resumitting this after having rebased it against the latest changes. The gaming line of Logitech devices doesn't use the old hidpp20 feature for battery level reporting. Instead, they report the current voltage of the battery, in millivolts.
This patch set handles this case by adding a quirk to the devices we know to have this new feature, in both wired and wireless mode. This version of the patch set is better split, as well as adding the quirk to make sure we don't needlessly probe every device connected.
