net: hisilicon: Fix potential use-after-free in hisi_femac_rx()

The skb is delivered to napi_gro_receive() which may free it, after
calling this, dereferencing skb may trigger use-after-free.

Fixes: 542ae60a ("net: hisilicon: Add Fast Ethernet MAC driver")
Signed-off-by: Liu Jian <liujian56@huawei.com>
Link: https://lore.kernel.org/r/20221203094240.1240211-1-liujian56@huawei.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>