app/pdump: fix vdev cleanup

app/pdump: fix vdev cleanup

Virtual devices added in pdump application
using rte_eal_hotplug_add should be removed explicitly
while exiting the pdump application, otherwise the
subsequent run of the pdump application will fail with the reason
that virtual devices with the same name already exists in primary.

Fixes: 6362f362a2 ("app/pdump: use EAL hotplug instead of ethdev attach")
Cc: stable@dpdk.org
Signed-off-by: Reshma Pattan <reshma.pattan@intel.com>
Tested-by: Ferruh Yigit <ferruh.yigit@intel.com>