USB: serial: option: add Sierra Wireless EM9191

USB: serial: option: add Sierra Wireless EM9191

Add support for the AT and diag ports, similar to other qualcomm SDX55
modems. In QDL mode, the modem uses a different device ID and support
is provided by qcserial in commit 11c52d250b34 ("USB: serial: qcserial:
add EM9191 QDL support").

T:  Bus=08 Lev=01 Prnt=01 Port=01 Cnt=01 Dev#=  3 Spd=5000 MxCh= 0
D:  Ver= 3.20 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 9 #Cfgs=  1
P:  Vendor=1199 ProdID=90d3 Rev=00.06
S:  Manufacturer=Sierra Wireless, Incorporated
S:  Product=Sierra Wireless EM9191
S:  SerialNumber=xxxxxxxxxxxxxxxx
C:  #Ifs= 4 Cfg#= 1 Atr=a0 MxPwr=896mA
I:  If#=0x0 Alt= 0 #EPs= 1 Cls=02(commc) Sub=0e Prot=00 Driver=cdc_mbim
I:  If#=0x1 Alt= 1 #EPs= 2 Cls=0a(data ) Sub=00 Prot=02 Driver=cdc_mbim
I:  If#=0x3 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=(none)
I:  If#=0x4 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=30 Driver=(none)

Signed-off-by: Benoît Monin <benoit.monin@gmx.fr>
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>