test: release ring resources after PMD perf test
test: release ring resources after PMD perf test

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 <5a9b6465c065ff0e1fd5d2cb9eb2185e82f34247@arm.com>
Reviewed-by: Gavin Hu <207ee22c2cf71e20c5b5df8395050c07c07d8709@arm.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk