net: ethernet: ti: cpsw: Fix suspend/resume break

Commit bfe59032 ("net: ethernet:
ti: cpsw: use cpsw as drv data")changes
the driver data to struct cpsw_common *cpsw. This is done
only in probe/remove but the suspend/resume functions are
still left with struct net_device *ndev. Hence fix both
suspend & resume also to fetch the updated driver data.

Fixes: bfe59032 ("net: ethernet: ti: cpsw: use cpsw as drv data")
Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>