USB: serial: option: add Fibocom NL668 variants

Update the USB serial option driver support for the Fibocom NL668 Cat.4
LTE modules as there are actually several different variants.
Got clarifications from Fibocom, there are distinct products:
- VID:PID 1508:1001, NL668 for IOT (no MBIM interface)
- VID:PID 2cb7:01a0, NL668-AM and NL652-EU are laptop M.2 cards (with
  MBIM interfaces for Windows/Linux/Chrome OS), respectively for Americas
  and Europe.

usb-devices output for the laptop M.2 cards:
T:  Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  4 Spd=480 MxCh= 0
D:  Ver= 2.00 Cls=ef(misc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=2cb7 ProdID=01a0 Rev=03.18
S:  Manufacturer=Fibocom Wireless Inc.
S:  Product=Fibocom NL652-EU Modem
S:  SerialNumber=0123456789ABCDEF
C:  #Ifs= 5 Cfg#= 1 Atr=a0 MxPwr=500mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=02(commc) Sub=0e Prot=00 Driver=cdc_mbim
I:  If#= 1 Alt= 1 #EPs= 2 Cls=0a(data ) Sub=00 Prot=02 Driver=cdc_mbim
I:  If#= 2 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=(none)
I:  If#= 3 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=(none)
I:  If#= 4 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=(none)

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>