tipc: Remove per-connection sequence number logic

Remove validation of the per-connection sequence numbers on routable
connections, since routable connections are not supported by TIPC.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>