dpaa2-switch: do not enable the DPSW at probe time

We should not enable the switch interfaces at probe time since this is
trigged by the open callback. Remove the call dpsw_enable() which does
exactly this.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>