[SCTP]: sctp doesn't show all associations/endpoints in /proc

When creating a very large number of associations (and endpoints),
/proc/assocs and /proc/eps will not show all of them.  As a result
netstat will not show all of the either.  This is particularly evident
when creating 1000+ associations (or endpoints).  As an example with
1500 tcp style associations over loopback, netstat showed 1420 on my
system instead of 3000.

The reason for this is that the seq_operations start method is invoked
multiple times bacause of the amount of data that is provided.  The
start method always increments the position parameter and since we use
the position as the hash bucket id, we end up skipping hash buckets.

This patch corrects this situation and get's rid of the silly hash-1
decrement.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>