net: bridge: fix multicast-to-unicast with fraglist GSO

stable inclusion
from stable-v4.19.314
commit 01386957ca757e31fb66caceb303f71f9e577b83
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IA7IEQ

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=01386957ca757e31fb66caceb303f71f9e577b83



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[ Upstream commit 59c878cbcdd80ed39315573b3511d0acfd3501b5 ]

Calling skb_copy on a SKB_GSO_FRAGLIST skb is not valid, since it returns
an invalid linearized skb. This code only needs to change the ethernet
header, so pskb_copy is the right function to call here.

Fixes: 6db6f0ea ("bridge: multicast to unicast")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>