mscc: Configured MAC entries should be locked.

[ Upstream commit 8fd1a4affbdafda592f80cd01bf7a382a5ff2fe8 ]

The MAC table in Ocelot supports auto aging (normal) and static entries.
MAC entries that is manually configured should be static and not subject
to aging.

Fixes: a556c76a ("net: mscc: Add initial Ocelot switch support")
Signed-off-by: Allan Nielsen <allan.nielsen@microchip.com>
Reviewed-by: Steen Hegelund <steen.hegelund@microchip.com>
Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>