Specification links:
- CDC NCM errata link:
  http://www.usb.org/developers/devclass_docs/NCM10_012011.zip
- CDC and WMC errata link:
  http://www.usb.org/developers/devclass_docs/CDC1.2_WMC1.1_012011.zip

Changes:
- driver updated to match cdc.h header with errata changes
- added support for USB_CDC_SET_NTB_INPUT_SIZE control request with
  8 byte length
- fixes to comply with specification: send only control requests supported by
  device, set number of datagrams for IN direction, connection speed structure
  update, etc.
- packet loss fixed for tx direction; misleading flag renamed.
- adjusted hard_mtu value.
Signed-off-by: Alexey Orishko <alexey.orishko@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>