net/af_xdp: fix creating multiple instance
net/af_xdp: fix creating multiple instance

Naming the buf_ring and umem memzone dynamically allows
to create multiple af_xdp vdevs.

Fixes: f1debd77efaf ("net/af_xdp: introduce AF_XDP PMD")

Reported-by: Markus Theil <8d5584ed2ba091d398f480a39d3375bd5f6b9f38@tu-ilmenau.de>
Signed-off-by: Xiaolong Ye <c7d6fc2f7e22da80deb234d523238b510a8c0f08@intel.com>
Reviewed-by: David Marchand <f28529695cfa9e3e1eb84e7072aa626af4abb18e@redhat.com>

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