netdev-dpdk: Fix padding info comment.

The comment was incorrectly updated. Fix it to the
correct value of 36 pad bytes.

/* --- cacheline 5 boundary (320 bytes) --- */
union {
        struct {
                struct netdev_stats stats;       /*   320   336 */
                /* --- cacheline 5 boundary (320 bytes) was 16 bytes ago --- */
                uint64_t   tx_retries;           /*   656     8 */
                rte_spinlock_t stats_lock;       /*   664     4 */
        };                                       /*         352 */
        uint8_t            pad52[384];           /*         384 */
};                                               /*   320   384 */

Fixes: c161357 ("netdev-dpdk: Add custom stat for vhost tx retries.")
Reported-by: Ilya Maximets <i.maximets@samsung.com>
Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>

lib/netdev-dpdk.c

@@ -451,7 +451,7 @@ struct netdev_dpdk {
         uint64_t tx_retries;
         /* Protects stats */
         rte_spinlock_t stats_lock;
-        /* 4 pad bytes here. */
+        /* 36 pad bytes here. */
     );
 
     PADDED_MEMBERS(CACHE_LINE_SIZE,