Harmonize vec/pool_get_aligned object sizes and alignment requests

Object sizes must evenly divide alignment requests, or vice
versa. Otherwise, only the first object will be aligned as
requested.

Three choices: add CLIB_CACHE_LINE_ALIGN_MARK(align_me) at
the end of structures, manually pad to an even divisor or multiple of
the alignment request, or use plain vectors/pools.

static assert for enforcement.

Change-Id: I41aa6ff1a58267301d32aaf4b9cd24678ac1c147
Signed-off-by: Dave Barach <dbarach@cisco.com>
diff --git a/src/vnet/ipip/ipip.h b/src/vnet/ipip/ipip.h
index e9277d8..f52094f 100644
--- a/src/vnet/ipip/ipip.h
+++ b/src/vnet/ipip/ipip.h
@@ -68,6 +68,9 @@
  */
 typedef struct
 {
+  /* Required for pool_get_aligned */
+  CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
+
   ipip_mode_t mode;
   ipip_transport_t transport;
   ipip_tunnel_key_t *key;