net: sctp: sctp_auth_make_key_vector: use sctp_auth_create_key

In sctp_auth_make_key_vector, we allocate a temporary sctp_auth_bytes
structure with kmalloc instead of the sctp_auth_create_key allocator.
Change this to sctp_auth_create_key as it is the case everywhere else,
so that we also can properly free it via sctp_auth_key_put. This makes
it easier for future code changes in the structure and allocator itself,
since a single API is consistently used for this purpose. Also, by
using sctp_auth_create_key we're doing sanity checks over the arguments.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>