net/iavf: fix HW ring scan method selection

net/iavf: fix HW ring scan method selection

When setup Rx queue, the rxdid would be changed if it's
"IAVF_RXDID_LEGACY_0/1", that caused the scan HW ring used the wrong
function 'iavf_rx_scan_hw_ring_flex_rxd()'.

Ignore the rxdid changed when equals "IAVF_RXDID_LEGACY_0/1".

Fixes: 0ed16e01313e ("net/iavf: fix function pointer in multi-process")
Cc: stable@dpdk.org
Signed-off-by: Steve Yang <stevex.yang@intel.com>
Acked-by: Beilei Xing <beilei.xing@intel.com>