Avoid packet pointers copy in TxQ tx method

[tropuq]

Currently, packets that failed to be sent need to be copied to the beginning of the packet array. This, in some cases, can have some impact on the performance results.

rust-dpdk/bindings/dpdk/src/eal.rs

Line 945 in 5a1f27e

unsafe { ptr::copy(pkt_buffer.add(cnt), pkt_buffer, remaining) };