net: ethtool: add VxLAN to the NFC API

driver inclusion
category:feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I61CGU



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To support for steering VxLAN flows using the ethtool NFC interface, this
patch adds flow specifications for vxlan4(VxLAN with inner IPv4) and vxlan6
(VxLAN with inner IPv6).

Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: Jiantao Xiao <xiaojiantao1@h-partners.com>