net/af_xdp: specify minimal and maximal MTU
net/af_xdp: specify minimal and maximal MTU

Properly report mtu capability in port device info.

Reported-by: David Marchand <f28529695cfa9e3e1eb84e7072aa626af4abb18e@redhat.com>
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