vxge: fix sparse warning

this patch fixes following sparse warning:

vxge-config.c:4640:30: warning: Using plain integer as NULL pointer
Signed-off-by: NLad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/neterion/vxge/vxge-config.c

@@ -4637,7 +4637,7 @@ static void __vxge_hw_vp_terminate(struct __vxge_hw_device *hldev, u32 vp_id)
 	vpath->ringh = NULL;
 	vpath->fifoh = NULL;
 	memset(&vpath->vpath_handles, 0, sizeof(struct list_head));
-	vpath->stats_block = 0;
+	vpath->stats_block = NULL;
 	vpath->hw_stats = NULL;
 	vpath->hw_stats_sav = NULL;
 	vpath->sw_stats = NULL;