USB: serial: cp210x: add Silicon Labs 358x VID and PID

Enable Silicon Labs Ember VID chips to enumerate with the cp210x usb serial
driver. EM358x devices operating with the Ember Z-Net 5.1.2 stack may now
connect to host PCs over a USB serial link.

Signed-off-by: Nathaniel Ting <nathaniel.ting@silabs.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>