*: use void * for printing pointers

On higher warning levels, compilers expect %p printf arguments to be
void *.  Since format string / argument warnings can be useful
otherwise, let's get rid of this noise by sprinkling casts to void *
over printf calls.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/ospfd/ospf_spf.c b/ospfd/ospf_spf.c
index 1fe8ab4..6205b3e 100644
--- a/ospfd/ospf_spf.c
+++ b/ospfd/ospf_spf.c
@@ -1014,7 +1014,7 @@
     for (ALL_LIST_ELEMENTS_RO (v->parents, nnode, parent))
       {
         zlog_debug (" nexthop %p %s %s", 
-                    parent->nexthop,
+                    (void *)parent->nexthop,
                     inet_ntoa (parent->nexthop->router),
                     parent->nexthop->oi ? IF_NAME(parent->nexthop->oi)
                                         : "NULL");
@@ -1444,7 +1444,7 @@
     {
       if (IS_DEBUG_OSPF_EVENT)
         zlog_debug ("SPF: calculation timer is already scheduled: %p",
-                   ospf->t_spf_calc);
+                    (void *)ospf->t_spf_calc);
       return;
     }