Need to release the port and the ring resources after test. Otherwise,
it will cause failure to allocate memory when reentry the test.
Fixes: ea764af ("app/test: add performance test for ring driver")
Cc: stable@dpdk.org
Signed-off-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Gavin Hu <gavin.hu@arm.com>
bc44d44847