PKT_SCHED: cls_basic: Use unsigned int when generating handle

PKT_SCHED: cls_basic: Use unsigned int when generating handle

gcc-4.1 and later take advantage of the fact that in the
C language certain types of overflow/underflow are undefined,
and this is completely legitimate.

Prevents filters from being added if the first generated
handle already exists.

Signed-off-by: Kim Nordlund <kim.nordlund@nokia.com>
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>