flow_offload: Reject matching on layer 2 miss

flow_offload: Reject matching on layer 2 miss

Adjust drivers that support the 'FLOW_DISSECTOR_KEY_META' key to reject
filters that try to match on the newly added layer 2 miss field. Add an
extack message to clearly communicate the failure reason to user space.

The following users were not patched:

1. mtk_flow_offload_replace(): Only checks that the key is present, but
   does not do anything with it.
2. mlx5_tc_ct_set_tuple_match(): Used as part of netfilter offload,
   which does not make use of the new field, unlike tc.
3. get_netdev_from_rule() in nfp: Likewise.

Example:

 # tc filter add dev swp1 egress pref 1 proto all flower skip_sw l2_miss true action drop
 Error: mlxsw_spectrum: Can't match on "l2_miss".
 We have an error talking to the kernel

Acked-by: Elad Nachman <enachman@marvell.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>