net: socionext: fix xdp_result initialization in netsec_process_rx

Fix xdp_result initialization in netsec_process_rx in order to not
increase rx counters if there is no bpf program attached to the xdp hook
and napi_gro_receive returns GRO_DROP

Fixes: ba2b2321 ("net: netsec: add XDP support")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>