net: ethernet: ti: cpsw: replace pdev on dev

No need to hold pdev link when only dev is needed.
This allows to simplify a bunch of cpsw->pdev->dev now and farther.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Reviewed-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>