[SCTP]: Fix sctp_assoc_seq_show() panics on big-endian systems.

This patch corrects the panic by casting the argument to the
pointer of correct size.  On big-endian systems we ended up loading
only 32 bits of data because we are treating the pointer as an int*.
By treating this pointer as loff_t*, we'll load the full 64 bits
and then let regular integer demotion take place which will give us
the correct value.

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