net: dsa: felix: delete workarounds present due to SVL tag_8021q bridging

The felix driver, which also has a tagging protocol implementation based
on tag_8021q, does not care about adding the RX VLAN that is pvid on one
port on the other ports that are in the same bridge with it. It simply
doesn't need that, because in its implementation, the RX VLAN that is
pvid of a port is only used to install a TCAM rule that pushes that VLAN
ID towards the CPU port.

Now that tag_8021q no longer performs Shared VLAN Learning based
forwarding, the RX VLANs are actually segregated into two types:
standalone VLANs and VLAN-unaware bridging VLANs. Since you actually
have to call dsa_tag_8021q_bridge_join() to get a bridging VLAN from
tag_8021q, and felix does not do that because it doesn't need it, it
means that it only gets standalone port VLANs from tag_8021q. Which is
perfect because this means it can drop its workarounds that avoid the
VLANs it does not need.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>