dpaa2-switch: set interface MAC address only on endpoint change

There is no point in updating the MAC address of a switch interface each
time the link state changes, this only needs to happen in case the
endpoint changes (the switch interface is [dis]connected from/to a MAC).

Just move the call to dpaa2_switch_port_set_mac_addr() under
DPSW_IRQ_EVENT_ENDPOINT_CHANGED.

Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>