net: cdc_ncm: return proper error if setup fails

Most setup errors are ignored to ensure maximum firmware
compatibilty.  But GET_NTB_PARAMETERS and the functional
descriptors are required.  Use proper error codes and
log level if these fail.

Cc: Alexey Orishko <alexey.orishko@gmail.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>