net: dsa: sja1105: Make sja1105_is_link_local not match meta frames

Although meta frames are configured to be sent at SJA1105_META_DMAC
(01-80-C2-00-00-0E) which is a multicast MAC address that would also be
trapped by the switch to the CPU, were it to receive it on a front-panel
port, meta frames are conceptually not link-local frames, they only
carry their RX timestamps.

The choice of sending meta frames at a multicast DMAC is a pragmatic
one, to avoid installing an extra entry to the DSA master port's
multicast MAC filter.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>