trace: fix crash when exiting

trace: fix crash when exiting

Bug scenario:
1. start testpmd:
  $ dpdk-testpmd -l 4-6 -a 0000:7d:00.0 --trace=.* -- -i
2. quit testpmd and then observed segment fault:
  Bye...
  Segmentation fault (core dumped)

The root cause is that rte_trace_save() and eal_trace_fini() access
the huge pages which were cleanup by rte_eal_memory_detach().

This patch moves rte_trace_save() and eal_trace_fini() before
rte_eal_memory_detach() to fix the bug.

Fixes: dfbc61a2f9a6 ("mem: detach memsegs on cleanup")
Cc: stable@dpdk.org
Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
Tested-by: Jerin Jacob <jerinj@marvell.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>