net: dsa: mv88e6xxx: replace VTU violation prints with trace points

commit 9e3d9ae5 upstream.

It is possible to trigger these VTU violation messages very easily,
it's only necessary to send packets with an unknown VLAN ID to a port
that belongs to a VLAN-aware bridge.

Do a similar thing as for ATU violation messages, and hide them in the
kernel's trace buffer.

New usage model:

$ trace-cmd list | grep mv88e6xxx
mv88e6xxx
mv88e6xxx:mv88e6xxx_vtu_miss_violation
mv88e6xxx:mv88e6xxx_vtu_member_violation
$ trace-cmd report

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Saeed Mahameed <saeed@kernel.org>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Cc: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>