[NETNS][DST] dst: pass the dst_ops as parameter to the gc functions

The garbage collection function receive the dst_ops structure as
parameter. This is useful for the next incoming patchset because it
will need the dst_ops (there will be several instances) and the
network namespace pointer (contained in the dst_ops).

The protocols which do not take care of the namespaces will not be
impacted by this change (expect for the function signature), they do
just ignore the parameter.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dst.c b/net/core/dst.c
index 7eceeba..7deef48 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -165,7 +165,7 @@
 	struct dst_entry * dst;
 
 	if (ops->gc && atomic_read(&ops->entries) > ops->gc_thresh) {
-		if (ops->gc())
+		if (ops->gc(ops))
 			return NULL;
 	}
 	dst = kmem_cache_zalloc(ops->kmem_cachep, GFP_ATOMIC);