[NET] Fix X.25 use after free.

[NET] Fix X.25 use after free.

The conversion from cli/sti to locking in X.25 must not have been tested
on a real SMP with memory debugging enabled.  It OOPS right away if
I do:
        modprobe x25; ifconfig -a

The problem is that it dereferences the socket after it has already been
freed.  The fix for this is to make the call to sock_put, later in
x25_destroy_socket do the free.  Also, need a go to avoid references
in x25_release.