sctp: fix some indents in sm_make_chunk.c

There are some bad indents of functions' defination in sm_make_chunk.c.
They have been there since beginning, it was probably caused by that
the typedef sctp_chunk_t was replaced with struct sctp_chunk.

So it's the best time to fix them in this patchset, it's also to fix
some bad indents in other functions' defination in sm_make_chunk.c.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>