FIB: correctly report IPv6 FIB Unicast and Multicast memory usage (VPP-1578)"

and document scaling

Change-Id: I65d8999e65616d77e525963c770d91e9b0d5e593
Signed-off-by: Neale Ranns <nranns@cisco.com>
diff --git a/src/vnet/fib/ip4_fib.c b/src/vnet/fib/ip4_fib.c
index 57fc23b..8944637 100644
--- a/src/vnet/fib/ip4_fib.c
+++ b/src/vnet/fib/ip4_fib.c
@@ -566,12 +566,12 @@
 format_ip4_fib_table_memory (u8 * s, va_list * args)
 {
 #if USE_DLMALLOC == 0
-    s = format(s, "%=30s %=6d %=8ld\n",
+    s = format(s, "%=30s %=6d %=12ld\n",
                "IPv4 unicast",
                pool_elts(ip4_main.fibs),
                mheap_bytes(ip4_main.mtrie_mheap));
 #else
-    s = format(s, "%=30s %=6d %=8ld\n",
+    s = format(s, "%=30s %=6d %=12ld\n",
                "IPv4 unicast",
                pool_elts(ip4_main.fibs),
                mspace_footprint(ip4_main.mtrie_mheap));