net: ethernet: ti: cpsw: allow untagged traffic on host port

Now untagged vlan traffic is not support on Host P0 port. This patch adds
in ALE context bitmap of VLANs for which Host P0 port bit set in Force
Untagged Packet Egress bitmask in VLANs ALE entries, and adds corresponding
check in VLAN incapsulation header parsing function cpsw_rx_vlan_encap().

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>