staging: dgnc: fixes ioctl param list

The declaration for the ioctl function has changed. The previous version
of this declaration took struct file *file as a parameter and the new
one does not. This patch removes that parameter.

Signed-off-by: Lidza Louina <lidza.louina@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>