Commit 9e5baf9b ("net: dsa: mv88e6xxx: add RMU disable op")
introduced .rmu_disable() method with implementation for several models,
but forgot to add Topaz, which can use the Peridot implementation.

Use the Peridot implementation of .rmu_disable() on Topaz.
Signed-off-by: NMarek Behún <kabel@kernel.org>
Fixes: 9e5baf9b ("net: dsa: mv88e6xxx: add RMU disable op")
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>