USB: whiteheat: fix memory leak in error path

Make sure command buffer is deallocated in case of errors during attach.

Cc: <support@connecttech.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/whiteheat.c

@@ -333,6 +333,7 @@ no_firmware:
 		"%s: please contact support@connecttech.com\n",
 		serial->type->description);
 	kfree(result);
+	kfree(command);
 	return -ENODEV;
 
 no_command_private: