net: remove bond_slave_has_mac_rcu()

stable inclusion
from stable-v4.19.293
commit ed8528e17f31264cbe6b6655c9eff02715bfd195
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I85XNK
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ed8528e17f31264cbe6b6655c9eff02715bfd195



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[ Upstream commit 8b0fdcdc ]

No caller since v3.16.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: e74216b8 ("bonding: fix macvlan over alb bond support")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>