Huawei's usage of the subclass and protocol fields is not 100%
clear to us, but there appears to be a very strict system.

A device with the "shared" device ID 12d1:1506 and this NCM
function was recently reported (showing only default altsetting):

    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass      3
      bInterfaceProtocol     22
      iInterface              8 CDC Network Control Model (NCM)
      ** UNRECOGNIZED:  05 24 00 10 01
      ** UNRECOGNIZED:  06 24 1a 00 01 1f
      ** UNRECOGNIZED:  0c 24 1b 00 01 00 04 10 14 dc 05 20
      ** UNRECOGNIZED:  0d 24 0f 0a 0f 00 00 00 ea 05 03 00 01
      ** UNRECOGNIZED:  05 24 06 01 01
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x85  EP 5 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0010  1x 16 bytes
        bInterval               9

Cc: Enrico Mioso <mrkiko.rs@gmail.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>