net-next: dsa: fix duplicate invocation of set_addr()

commit 83c0afae ("net: dsa: Add new binding implementation")
has a duplicate invocation of the set_addr() operation callback. Remove one
of them.

Signed-off-by: John Crispin <john@phrozen.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>