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>

drivers/net/usb/cdc_ncm.c

@@ -86,8 +86,8 @@ static u8 cdc_ncm_setup(struct usbnet *dev)
 			      0, iface_no, &ncm_parm,
 			      sizeof(ncm_parm));
 	if (err < 0) {
-		dev_dbg(&dev->intf->dev, "failed GET_NTB_PARAMETERS\n");
-		return 1;
+		dev_err(&dev->intf->dev, "failed GET_NTB_PARAMETERS\n");
+		return err; /* GET_NTB_PARAMETERS is required */
 	}
 
 	/* read correct set of parameters according to device mode */