staging: dgnc: off by one in dgnc_mgmt_ioctl()

"dgnc_NumBoards" is the number of initialized elements in the
dgnc_Board[] array so the comparison should be ">=" instead of ">" so we
don't read invalid data.  We can remove the special handling of the
empty array now that we've fixed this bug.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>