USB: serial: kobil_sct: log failure to update line settings

Log failure to update the line settings in set_termios().

This also avoids a W=1 (-Wunused-but-set-variable) warning.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

drivers/usb/serial/kobil_sct.c

@@ -526,6 +526,10 @@ static void kobil_set_termios(struct tty_struct *tty,
 		  0,
 		  KOBIL_TIMEOUT
 		);
+	if (result) {
+		dev_err(&port->dev, "failed to update line settings: %d\n",
+				result);
+	}
 }
 
 static int kobil_ioctl(struct tty_struct *tty,