selinux: correctly handle sa_family cases in selinux_sctp_bind_connect()

Allow to pass the socket address structure with AF_UNSPEC family for
compatibility purposes. selinux_socket_bind() will further check it
for INADDR_ANY and selinux_socket_connect_helper() should return
EINVAL.

For a bad address family return EINVAL instead of AFNOSUPPORT error,
i.e. what is expected from SCTP protocol in such case.

Fixes: d452930f

 ("selinux: Add SCTP support")
Suggested-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>