USB: cp210x: add support for Corsair usb dongle

commit b9326057a3d8447f5d2e74a7b521ccf21add2ec0 upstream.

Corsair USB Dongles are shipped with Corsair AXi series PSUs.
These are cp210x serial usb devices, so make driver detect these.
I have a program, that can get information from these PSUs.

Tested with 2 different dongles shipped with Corsair AX860i and
AX1200i units.

Signed-off-by: Andras Kovacs <andras@sth.sze.hu>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>