Currently the driver allows to configure matching by VLAN EtherType.
However, the retrieval function does not report it back to the user. Add
it.

Before:
|root@host:~# ethtool -N enp3s0 flow-type ether vlan-etype 0x8100 action 0
|Added rule with ID 63
|root@host:~# ethtool --show-ntuple enp3s0
|4 RX rings available
|Total 1 rules
|
|Filter: 63
|        Flow Type: Raw Ethernet
|        Src MAC addr: 00:00:00:00:00:00 mask: FF:FF:FF:FF:FF:FF
|        Dest MAC addr: 00:00:00:00:00:00 mask: FF:FF:FF:FF:FF:FF
|        Ethertype: 0x0 mask: 0xFFFF
|        Action: Direct to queue 0

After:
|root@host:~# ethtool -N enp3s0 flow-type ether vlan-etype 0x8100 action 0
|Added rule with ID 63
|root@host:~# ethtool --show-ntuple enp3s0
|4 RX rings available
|Total 1 rules
|
|Filter: 63
|        Flow Type: Raw Ethernet
|        Src MAC addr: 00:00:00:00:00:00 mask: FF:FF:FF:FF:FF:FF
|        Dest MAC addr: 00:00:00:00:00:00 mask: FF:FF:FF:FF:FF:FF
|        Ethertype: 0x0 mask: 0xFFFF
|        VLAN EtherType: 0x8100 mask: 0x0
|        VLAN: 0x0 mask: 0xffff
|        User-defined: 0x0 mask: 0xffffffffffffffff
|        Action: Direct to queue 0

Fixes: 2b477d05 ("igc: Integrate flex filter into ethtool ops")
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Tested-by: Naama Meir <naamax.meir@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>