hash: fix total entries count

hash: fix total entries count

In rte_hash, with current implementation, it is possible that keys
are stored at indexes greater than the number of total entries.

Currently, in rte_hash_free_key_with_position(), due to incorrect
computation of total_entries, application cannot free keys with
indexes greater than the number of total entries.

This patch fixes this incorrect computation of total_entries.

Bugzilla ID: 261
Fixes: 9d033dac7d7c ("hash: support no free on delete")
Cc: stable@dpdk.org
Reported-by: Linfan <zhongdahulinfan@163.com>
Suggested-by: Linfan <zhongdahulinfan@163.com>
Signed-off-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
Acked-by: Yipeng Wang <yipeng1.wang@intel.com>