[DCCP] CCID2: Fix jiffie wrap issues

Jiffies are now handled correctly (I hope) in CCID2.  If they wrap, no
problem.

Signed-off-by: Andrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>