USB: cp210x: Add WAGO 750-923 Service Cable device ID

The WAGO 750-923 USB Service Cable is used for configuration and firmware
updates of several industrial automation products from WAGO Kontakttechnik GmbH.

Bus 004 Device 002: ID 1be3:07a6
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0
  bDeviceProtocol         0
  bMaxPacketSize0        64
  idVendor           0x1be3
  idProduct          0x07a6
  bcdDevice            1.00
  iManufacturer           1 Silicon Labs
  iProduct                2 WAGO USB Service Cable
  iSerial                 3 1277796751
  . . .

Signed-off-by: Anders Larsen <al@alarsen.net>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>