staging: dgnc: Fix unsigned value for less than zero

The "un->un_open_count" is unsigned variable, so it cannot
be less than zero.

Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed