USB: serial: option: add support for VW/Skoda "Carstick LTE"

commit 617c331d upstream.

Add support for VW/Skoda "Carstick LTE"

D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=1c9e ProdID=7605 Rev=02.00
S:  Manufacturer=USB Modem
S:  Product=USB Modem
C:  #Ifs= 4 Cfg#= 1 Atr=e0 MxPwr=500mA
I:  If#=0x0 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=(none)
I:  If#=0x1 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=(none)
I:  If#=0x2 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=(none)
I:  If#=0x3 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=(none)

The stick has AT command interfaces on interfaces 1, 2, and 3, and does PPP
on interface 3.

Signed-off-by: Florian Zumbiehl <florz@florz.de>
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>