CP2105, CP2108 and CP2102N have vendor requests that can be used to
retrieve the firmware version. Having this information available is
essential when trying to work around buggy firmware as a recent CP2102N
regression showed.

Determine and log the firmware version also for CP2105 and CP2108
during type detection at probe.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>