nfp: using napi_build_skb() to replace build_skb()

The napi_build_skb() can reuse the skb in skb cache per CPU or
can allocate skbs in bulk, which helps improve the performance.

Signed-off-by: Fei Qin <fei.qin@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Link: https://lore.kernel.org/r/20231026080058.22810-1-louis.peens@corigine.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>