The same plugin name was being added to the device from the quirk file more than
once, and so we enumerated the device *again* and tried to add a duplicate
device -- the device list correctly refusing to do so.
Check the plugin name does not already exist before adding it, and add a self
test to catch this for the future.
I2C doesn't have any specification for what is a probe and what is a more
destructive action. Sending tx_buf out on the i2c bus to a generic address
might not be safe in all cases.
To prevent this, use a HWID to check the machine DMI value during device
creation before ->probe() or ->setup() is called on the device.
Sometimes we only want to add the instance ID to get the quirk matches, and it
is confusing to see the "fake" IDs in the 'fwupdmgr get-devices' output.
