USB: serial: option: add support for Quectel RM500Q in QDL mode

Add support for Quectel RM500Q in QDL mode.

T:  Bus=02 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 24 Spd=480  MxCh= 0
D:  Ver= 2.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=2c7c ProdID=0800 Rev= 0.00
S:  Manufacturer=Qualcomm CDMA Technologies MSM
S:  Product=QUSB_BULK_SN:xxxxxxxx
S:  SerialNumber=xxxxxxxx
C:* #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr=  2mA
I:* If#= 0 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=10 Driver=option
E:  Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=01(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms

It is assumed that the ZLP flag required for other Qualcomm-based
5G devices also applies to Quectel RM500Q.

Signed-off-by: Reinhard Speyerer <rspmn@arcor.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>