netfilter: nf_tables_offload: check FLOW_DISSECTOR_KEY_BASIC in VLAN transfer logic

netfilter: nf_tables_offload: check FLOW_DISSECTOR_KEY_BASIC in VLAN transfer logic

BugLink: https://bugs.launchpad.net/bugs/1938340
[ Upstream commit ea45fdf82cc90430bb7c280e5e53821e833782c5 ]

The VLAN transfer logic should actually check for
FLOW_DISSECTOR_KEY_BASIC, not FLOW_DISSECTOR_KEY_CONTROL. Moreover, do
not fallback to case 2) .n_proto is set to 802.1q or 802.1ad, if
FLOW_DISSECTOR_KEY_BASIC is unset.

Fixes: 783003f3bb8a ("netfilter: nftables_offload: special ethertype handling for VLAN")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>