selinux: Fix error priority for bind with AF_UNSPEC on PF_INET6 socket

The IPv6 network stack first checks the sockaddr length (-EINVAL error)
before checking the family (-EAFNOSUPPORT error).

This was discovered thanks to commit a549d055

 ("selftests/landlock:
Add network tests").

Cc: Eric Paris <eparis@parisplace.org>
Cc: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Reported-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Closes: https://lore.kernel.org/r/0584f91c-537c-4188-9e4f-04f192565667@collabora.com
Fixes: 0f8db8cc

 ("selinux: add AF_UNSPEC and INADDR_ANY checks to selinux_socket_bind()")
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Tested-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>